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It may seem odd to lament a decrease in home runs for a player who has topped out at 21 in a season, but that’s exactly where we found ourselves after Dustin Pedroia finished an injury-marred 2014 with just seven bombs. Coming into this season, Pedroia’s power numbers were trending, and not in a good way.

Year PA TAv SLG
2010 351 .283 .493
2011 731 .295 .474
2012 623 .281 .449
2013 724 .289 .415
2014 609 .268 .376

True Average tells the story that Pedroia’s offensive production didn’t change a whole lot during the 2010-2013 period, before taking a significant drop in 2014. But in terms of how much of that production came in the form of extra base hits, it’s Pedroia’s slugging percentage that tells the dominant story — declining four consecutive times.

PECOTA didn’t fall for the 2014 dip, but it did expect a new normal for Pedroia, predicting that it was his 2013 that would set the tone this season. PECOTA’s .404 slugging percentage signaled that the older Pedroia wouldn’t be the Pedroia of old, but it did hold the line with production overall: a .282 True Average. If the first third of the season is any indication, however, it looks like Pedroia may have turned back the clock, at least to 2012: through Saturday, Pedroia had a .444 slugging percentage and .295 True Average.

If you were anything like me, you were hoping that Pedroia would pick his power back up, but that optimism was cautious. After all, the previous two seasons were marred by injury: thumb soreness and then ligament sprain, a whole bunch of bumps and bruises, wrist inflammation and then finally surgery. Having no frame of reference for “first dorsal compartment release with tenosynovestomy,” I’m not sure if any of us knew what to think. If injury helped to limit Pedroia the last two years, then that itself becomes part of the projection, maybe. It would at least be hard to project health, right?

As players ranging from Wil Myers to Derrek Lee can attest, wrist and hand injuries can definitely sap power, but only temporarily. As Nomar Garciaparra can attest, it isn’t necessarily temporary. And that matters, because it’s hard to see doing something like this without making maximum use of one’s hands and wrists (along with every other body part):

Reading the tea leaves, then, we have reasons to doubt and reasons to believe Pedroia’s power surge. Is this some evidence that Pedroia’s thumb and wrist woes were responsible for a power outage that was temporary? Or, after years of trend lines and background on aging curves to look at, how much do you trust a little extra power after just two months?

A few weeks ago, batted ball velocity made it look like Mike Napoli was due for a bounce back at the plate — maybe it can also help us sort out if Pedroia is going as well as his .444 slugging mark would indicate. Here are the buckets used when looking at Napoli:

Speed 31-74 mph 75-89 mph 90-99 mph 100+ mph
Tracked Balls 2416 4780 4995 3594
Hits 529 1048 1626 2147
Batting Avg .219 .219 .326 .597
Slugging Pct .245 .258 .483 1.180
Errors (%) 47 (1.9%) 59 (1.2%) 68 (1.4%) 45 (1.3%)

And here’s Pedroia so far this season, with MLB percentages also from the Napoli study:

Speed 31-74 mph 75-89 mph 90-99 mph 100+ mph
MLB, % of tracked balls 15.3% 30.3% 31.6% 22.8%
Pedroia, of 125 (%) 19 (15.2%) 36 (28.8%) 58 (46.4%) 12 (9.6%)
Pedroia BA .222 .167 .446 .833
Pedroia SLG .222 .167 .643 1.755

With the exception of being particularly shift-able or shift-proof, sustaining BABIPs higher or lower than league average are a function of two things: foot speed (beating out infield hits), and hitting the ball hard. Slugging percentage is kind of a different animal, however, although it still relies on those two things. Infield hits don’t much help there, and it’s rare to leg out a home run — so while foot speed can help a player take an extra base, slugging percentage is probably more a function of hard hits.

These arbitrary buckets make it look like Pedroia struggles to hit an average number of the hardest hit balls, but even with the small numbers, it’s remarkable how well he fits MLB averages. If you think of some of the 100+ mph batted balls as being moved into the 90-99 mph bucket, the rest is an exact match. Pedroia’s foot speed is far from a liability, and he has had eight infield hits already this year — and maybe that’s enough for us to say that his .307 BABIP overall isn’t that lucky.

Where comparing batted ball velocity to league averages made Napoli look particularly unlucky, however, it looks like Pedroia has been spectacularly lucky with respect to the bases he’s totaled in the 100+ mph and 90-99 mph buckets. Without testing more players and having a much longer time period to go on, there’s no easy way to know whether individual types of players might routinely fare differently as far as batted ball data is concerned — and yet, it’s really hard to come up with a rationale for why.

In terms of hardest-hit balls, then, Pedroia probably has been lucky — two of Pedroia’s 90-99 mph batted balls have turned into home runs, which is about what we should expect, but with 5 of his 12 batted balls tracked at 100+ mph turning into home runs — he’s probably not going to continue to put the ball over the fence at the same rate for the rest of the year. That’s the bad news.

The good news: in terms of balls tracked at 75-89 mph, Pedroia appears to have been unlucky, his .167 slugging well below the .258 for MLB. And it’s not like he happens to have had a bunch grouped toward the bottom of that velocity range, either; 24 of the 36 batted balls in that bucket were 85 mph or faster. Pedroia has actually been cheated in terms of the more softly-hit balls. It’s a big enough difference that if you were to use apply MLB averages for slugging to how Pedroia’s batted balls have actually been distributed among the four buckets, you’d get an “expected slugging” of .448 — actually a bit higher than Pedroia’s .444.

In terms of home runs, we shouldn’t expect Pedroia to finish the season with over 20 — if his batted ball velocity profile stays more or less the same, he might finish around 15. If batted ball velocity is any guide, however, Pedroia is back — and he’s bringing the extra base hits with him.

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