There was a time when goliaths roamed the Earth. Runs were plentiful, and with few natural enemies, these behemoths could grow larger and larger, more and more sedentary. They had no need to run, so they lumbered about, leisurely returning home unmolested by predator or foe.

But the metaphor could not last forever. Eventually, offense in baseball went back down to more typical levels, and the game once again welcomed back the singles hitter, the glove man, the productive out. And, as runs went down, stolen bases went up. I gave the following graph, showing leaguewide scoring and stolen base totals by year, a pun title. 

That’s the narrative, and it’s a good one. No problems with that narrative. Offense goes down, stolen bases go up. With runs at a premium, home runs less available, and basestealers getting better and better at avoiding caught stealings, the small-ball tactic takes on great significance.

What’s weird is that 2013 has disrupted the narrative, so far at least, and it’s not easy to say why. Here’s the same chart above, but with runs and stolen bases (prorated across a full season) added for 2013:

Brett Gardner is still looking for his first stolen base; Carlos Gomez got his first on Thursday. Michael Bourn, Mike Trout, and Jose Altuve have one each. Last year, teams attempted .89 steals per game; this year, they've attempted .69 steals per game.

So what’s to blame? Easier to rule out what’s not to blame, or probably not to blame, and see what’s left.

1. A gradual league-wide shift in style of play is not to blame.

As noted in the graphs above, the trend has been toward the stolen base, rather than away from it. If we go back to the beginning of the century, the most steal-happy seasons—both by attempts and by successful thefts—have come in the past two years:

Year Steals Attempts
2000 2924 4924
2001 3103 5104
2002 2750 4752
2003 2573 4576
2004 2589 4593
2005 2565 4570
2006 2767 4773
2007 2918 4925
2008 2799 4807
2009 2970 4979
2010 2959 4969
2011 3279 5290
2012 3229 5241

So this is an abrupt turnaround. 

2. Basestealers being more choosy aren’t to blame.

Technically, they are choosing not to steal, so that is literally the reason. But it isn’t like baserunners all realized that getting caught's not worth it and decided they're not going to steal unless it’s a sure thing that they'll be safe. The league’s 73.4 percent success rate through the first 13 games is about identical to the league’s 73.5 percent success rate through the first 13 games of years 2007 through 2012; it’s only slightly better than the 73.1 percent overall success rate since 2007. Which is all just to say that this isn't a stolen bases phenomenon but a stolen base attempts phenomenon. 

3. The particular characteristics unique to the month of April are not to blame.

You might guess that the first two weeks would be a slow time for stolen bases—weather, and injury concerns, and players working their way back to full speed. It’s not. From 2000 to 2012, teams attempted .827 steals per game in their first 13 games. They attempted .827 steals per game in their final 149 games.

All the same, if we compare 2013 thus far to the previous dozen years at comparable points (which is to say, the first 13 games of each team’s season, 13 being the number I’m choosing because there are teams this season that have played only 13 games), we have to go back a full decade to find a season as uninterested in basestealing as this one:

Year SBs, first 13 games Attempts, first 13 games
2000 216 343
2001 220 329
2002 227 346
2003 180 276
2004 216 297
2005 208 298
2006 200 279
2007 212 289
2008 247 340
2009 227 312
2010 273 359
2011 281 372
2012 249 354
2013 196 267

Comparing apples to apples, there are 87 stolen bases missing since last year. 

4. The limited predictive power of mid-April statistics is probably not to blame.

The correlation between the league’s first 13 games and its final 149 games over the past decade is .63. There’s certainly room there for this to turn out to be a fluke, but that’s a solid correlation.  

5. A lack of stolen base opportunities is not primarily to blame.

If, for instance, there just weren’t as many baserunners reaching first base (and OBP is down from last year, a tick), or if there weren’t as many baserunners reaching first base without a runner on second base, or if there weren’t as many baserunners reaching first base with two outs and without a runner on second or third (the most common basestealing situation) then that would explain it. That doesn’t explain it, because that’s not the case.

There are 24 base/out situations. Ten of them are either completely non-stealing situations (no runner on base) or de facto non-stealing situations (runner on third, bases loaded, etc). Of the other 14, baserunners are attempting to steal less frequently in 13 this season.

For instance, with a runner on first and two outs last year, baserunners stole second base or were caught stealing second base 10.76 percent of the time. In 2013, a runner has been on first with two outs 1,039 times. If 10.76 percent of those baserunners attempted to steal, there would be 112 attempts; in fact, there have been 94 attempts. Repeat that math for every situation, and it adds up to 97 missing stolen base attempts, based on this year's stolen base opportunities. 

6. A preponderance of blowouts, if it existed, would not be to blame.

There have been somewhat more plate appearances this year in blowouts (a lead or deficit of five runs or greater), but even if it were a very significant disparity (it’s not) it wouldn’t be to blame. The league is stealing less often in tie games, in one-run games, in two-run games, in three-run games, in four-run games, and in blow-outs.

7. High-profile basestealers not getting on base are not primarily to blame.

Some of them might be, I guess. But there are 239 baserunners who have attempted to steal less often this year than they did last year, and just 90 who have attempted to steal more often. If every individual runner who reached first base stole at exactly the same rate that he stole last year—that is, Trout stole as often as Trout stole last year; Kelly Shoppach stole as often as Kelly Shoppach stole last year; etc.—there'd be roughly 83 more steal attempts than we've seen.

8. The temperature is not to blame.

A popular theory among BP authors is that the cold weather this spring would make baserunners more cautious, for fear of injury. It’s true that there have been more games in the 30s and 40s in the first two weeks of this year than in the first two weeks of the past three years; it’s not all that close:

Temp 2010-2012 2013
0-39 degrees 1% of games 6%
40-49 degrees 11% 18%
50-59 degrees 26% 17%
60-60 degrees 32% 32%
70-79 degrees 23% 22%
80+ degrees 8% 5%
Except that stolen base attempts have been higher in low temperatures. Attempts per game at each temperature tier: 
Temp 2010-2012 2013
0-39 1.75 0.88
40-49 0.87 0.76
50-59 0.89 0.66
60-60 0.87 0.65
70-79 0.94 0.65
80+ 0.98 0.60
And so what ideas does that leave? It leaves dampness and precipitation, for one. There's been a lot of dampness and precipitation! But the weather data at Baseball-Reference is much less helpful on dampness and precipitation than it is for temperatures. It leaves some heretofore unnoticed trend in pitchers holding baserunners on more closely or more effectively, which can't be confirmed because it hasn't yet been noticed. It leaves … well, you tell me. What's it leave? You suggest it, I'll try to check it out. 

Thanks to Colin Wyers for research assistance. 

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Hi Doug, what about:
1) lack of familiarity with the opposing pitcher/catcher batteries because of the new schedule format?
2) inexperience of players on roster, attributable to widespread injuries?
3) government mind control?

A fun look at SBs. Thanks!
It could be deliberate, right? A sudden philosophical trend away from the SB. Has anything like that happened before? Can any new strategy be explained by philosophy rather than how it plays on the field.

I'd be curious about contact % this year, too. I'm biased by the stories of Gardner and Dunn's new effort to become contact hitters -- is this a trend? Are the lack of SBs a similar trend?
Honestly, not sure this isn't the answer, but it's sooo sudden and there wasn't even a hint of it really last year, and we haven't heard anything about it from players/managers, and it's leaguewide, so it's one heck of a sudden philosophical zig.
Actually, though, would we say it IS league-wide? Or is the stark reduction in attempts by a few teams tilting the numbers? We'd want to know what the usual SBA distribution for the early going is, and compare it to this year's. I mean, Boston has attempted 20 steals. Colorado has. The Indians, Astros, Angels and Yankees have just 25 attempts between them.

Now, I don't think the reasons for those teams' low attempts totals are strategic. I think they're accidents. I think the Indians might be doing some number-crunching and deciding to wait it out, but the Angels' drop is injury-related. The Astros' is about their .301 team OBP. The Yankees' is because they're anceint. Viewed this way, I sort of think the drop could be coincidence stemming from a few teams being in weird positions early on. Still just guessing though.
You said that it's not high profile baserunners not getting on base more often due to the fact that more baserunners are attempting to steal less often this year than more often. You also said its not a lack of stolen base opportunities. I think it would be interesting to still look at a combination of the two. Are guys that attempted 15+ steals last year not getting as many opportunities? Are those opportunities they are getting against superior batteries, so that it's less attractive to steal? I think it's still early enough in the year that some simple randomness like this could skew the results.

Another thing that you mention in the introduction but don't look at here: how has power this year compared to previous years? The argument is that power has been down in recent years so baserunners become more aggressive. Maybe managers and players are more cautious on the basepaths due to an abnormal spike in power early in the year.
I downloaded the league totals for games, homeruns, stolen bases, and caught stealing from 2002-2013 and then calculated the per game average for each of these statistics each year. I regressed total stolen base attempts on 1 year lagged homeruns. The R-Squared is 0.6914, the constant has a value of 1.69598, and the beta for lagged homeruns is -.8502404. With these estimates and the homeruns/game in 2012, the predicted stolen base attempts for 2013 would be .8327, which is between the current year's .706667 and the previous two years' 0.89814 and 0.93454, respectively.

I realize this is sloppy statistics, but I am just trying to give weak evidence to my point that this is probably due to a combination of an increase in power last year relative to the two years prior and the relative small sample of only being 13 games into this season.
Is it Mike Trout's extra 40 lbs?
Good point.
Been wondering why Trout hasn't run more. I think the new spot in the order is hurting. He's had several chances to run. Not like the Angels have been scoring lots of runs, seems like they'd try and scratch a few more out. Scioscia turning into Earl Weaver?
Mike Scioscia is the most or second-most aggressive manager in baseball when it comes to stealing bases. I'd be stunned if that had changed, given the efficiency and profligacy of so many of their runners (Aybar, Bourjos, Trout). I think in the Angels' case, it's absolutely just a blip that will correct itself.
I was watching the Angels and when Trout got on in front of Pujols, my first thought was that this is the upside of his batting second - he can steal in front of Pujols and prevent Albert from grounding into 40 DPs this year. He never made a move and Pujols grounded into a DP. The next time this happened, Trout stayed anchored to first and Pujols made a routine out, leaving him there. As soon as Hamitlon stepped in, Trout got runnerish, trying to steal twice (both fouled off by Hamilton), even though it took away the hole from a left-handed batter. It's a small sample size, but for whatever reason, it does appear that Trout's not running in front of Pujols. It could be that Scoscia fears the IBB which would follow the successful steal (especially with Hamilton being cold), or that Pujols doesn't like people running while he's up - some hitters are like that.
None of this explains the wider trend, of course.
COuld there just be fewer fast enough players to try stealing? The Cardinals have attempted only five steals all year. Well, that's probably in part because Pete Kozma is a lot, lot slower than Rafael Furcal. The Yankees have only attempted six steals, partially because Curtis Granderson and Derek Jeter are on the shelf. The Astros replaced their entire team with Carlos Pena and Chris Carter; they have tried just seven steals. I'm at a loss to explain the Indians (five attempts), but the Angels have tried just seven steals, and part of that is Pujols is hobbled, and part is that Erick Aybar is hurt.

Just a notion.
Brett Gardner is healthy this year; Jacoby Ellsbury is healthy this year; Carl Crawford is healthy this year; etc, so there are examples that go in both directions.

It's not a bad notion, but we looked at individual players from year to year (so, eliminating the effect of "disappearing" players) and most are stealing less often.
SBs aren't as Sports Center friendly. The decline of the game in one statistic.
I blame sabermetrics!

Seriously, managers now read BP and see that success rates below a certain threshold (76% or something?) are counterproductive. So green lights only for those most likely to get above that threshold...
And also to @huztlers: The question isn't why are stolen bases going down compared to 20 years ago, or 10 years ago, or even five years ago. It's why are they going down compared to 20 *games* ago. There hasn't been a sabermetric revolution in the past 20 games.
I loved that last line.

I'd like to think there will be a inflation back to the mean. Right now we're seeing less attempts, but we're seeing typical success rates. In 2011, the success rate over the first 13 games was .755. In 2012, the success rate was .703. This year that rate is in between at .734. I think we're looking at this as a statistical anomaly, when it's fairly typical. The steals aren't so far off to say there HAS to be something in strategy or a breakthrough in the way managers think about baserunning. It's a small sample size in a long season. Patience, maybe?
Sam, do you think hitting Cano in the 2 hold behind Gardner has caused Girardi to be a tad reticent about sending Gardner more?
I don't know if Gardner has had the green light less often, but he told me when I talked to him this week that Cano hitting behind him is why he hasn't been going. See here.
“My job is to get on base, especially with the way our lineup is right now,” Gardner said. "[Robinson] Cano’s hitting behind me, so I need to get on first base, and stay right there. It’s not a case of me trying to get on and steal second and leave first base open. I’m trying to leave that hole open for him.”

Got it!

Thanks Ben.
Couldn't the same be explained for Trout also? Most nights, he bats behind Bourjos, but he's always in front of Pujols, Hamilton, and Trumbo. If you were Scoscia, would you risk having a guy get to second or an extra run on the board when one of those three hits a home run? I think that's an unnecessary risk, don't you?
But last year Trout usually had Hunter and Pujols behind him. And it's not like this year's middle hitters have been racking up HRs.

Sosh does seem to think in theory rather than the current reality.
Are players, managers more cognizant of the injury risk of stolen bases? We certainly got a gruesome reminder of that with Jose Reyes.
How does the team-by-team data go? Is it a manager thing?
What about the combination of two or more factors - - for example longer spring training plus damp weather. Managers/players already preconditioned to be wary of more injuries early in year with longer spring training and then damp weather feeds into these concerns and triggers less running ...
Dampness and precipitation could be the culprit. It makes intuitive sense to me that managers would send their runners less often on wet basepaths.

It could also be a massive groundskeeper conspiracy.
I picture the groundskeepers in underground tunnels, using magnets to hold the runner's metal cleats in place. Motives: unclear.
Random thoughts:

1) Big skew in terms of RS. If you throw the bottom couple teams (e.g., the Marlins and their 2 RS/G) out of the equation, is run scoring still down?

2) People are taking an extra base 40% of the time, vs 41% last year. So similar it's hard to argue a 'base-path condition' explanation.

3) SB% is about the same as last year, indicating that if they did steal as much as last year it would be lower (Assuming diminishing marginal returns). So for whatever reason the conditions for stealing bases is worse, even if SB% is the same (since there's a selection bias where people don't choose their attempts at random, instead choosing the best opportunities).

4) Catcher (net) changes from last opening day: +Flowers +S. Perez, +Cervilli, +Jaso, +J Montero, +Laird, +Castillo, +Rosario, +Kratz, +Brantley, -Ruiz, -McCann, -Suzuki, -Olivo, -Soto, -Torrealba, -Pena, -Hernandez, -Thole, -Barajas. I don't know all that much about catcher defense, so I can't instinctively guess the sign of that effect (Assuming opening day starting correlates with more play the first 20 games). There are some stinkers on both lists, to be sure.
Net manager changes could also be there (but if that were the case, you would expect to see lower SB but higher SB%, unless more conservative managers just suck at figuring out when to run).
Occam's razor seems to be shaving off everything except that .63 correlation.
More interleague early in the season?

NL teams that tend to steal may be stealing less in games with a DH.

And it's not offset by AL teams forced to bat their pitcher because they haven't constructed their rosters to use speed the way NL teams have.

No clue if it's true, but seems logical.
I blame Juan Segura.
I'm late to the party on this one, but I think manager changes, lineup changes (as discussed already) and injury concerns are enough to explain the 83 less attempts this year. I can easily account for 14 of those (almost 20%) just from 3 players on one team - the Indians. After the first 17 games last year, Michael Bourn, Jason Kipnis and Drew Stubbs had a combined 18 attempts. This year they have 4. But Stubbs and Bourn didn't play for the Indians last year. And Terry Francona didn't manage the Indians last year. Looking at Red Sox stats through Francona's time, it's pretty clear he doesn't like to send the runners. They were near the bottom of AL in attempts for 6 of his 8 seasons there. It doesn't seem unreasonable that the impacts of new batting orders, interleague, and new managers could easily add up to the 80-some "missing" steals.
Jacoby Ellsbury stole 70 bases in a season while Francona was there, which is the most any AL baserunner has stolen in a season since 1997
True. And so is: "They were near the bottom of AL in attempts for 6 of his 8 seasons there." 2009 was one of the 2 other years. And they were still only 5th with Ellsbury.