Last week, Matt Trueblood wrote about the biggest changes to team Playoff Odds since the start of the season. The five teams with the widest swings: The White Sox, Red Sox, Astros, Mariners, and Yankees. You can guess why. Three of them have been surprisingly good, and two of them have been surprisingly bad. Those teamwide surprises have been underpinned by individual surprises, like Jackie Bradley Jr. (good) and Dallas Keuchel (not). Surprises all, but well-known surprises. If Donald Rumsfeld were writing for BP, he might call them known knowns. (He might call them that anyway. Or he might be too focused on getting you to play solitaire on your smartphone to care.)

I’m looking for unknown knowns. These are teams that’ve changed in less obvious ways—i.e., not the ones you see when you peruse the standings each day—but are nonetheless interesting. I looked for sharp changes from 2015 compared to the 2016 season to date that have probably eluded headlines and highlight shows.

Of course, there are two ways a team can change. They can import a bunch of new players with new characteristics, or their existing personnel can change. I found a little of both in this list.

The Washington Nationals: Not Goin’ Oppo
In 2015, Nationals batters hit 26.8 percent of their balls in play to the opposite field. That was the seventh highest percentage in the majors. This year, the figure’s dropped to 23.1 percent, lower than any team but the pull-happy Rays.

This change is mostly personnel-related. Catcher Wilson Ramos has pulled a lot more this year (and produced a lot more), with an opposite-field percentage down from 27 percent to 24 percent; right fielder Jayson Werth is also hitting fewer the opposite way (down from 32 percent to 21 percent). On the other hand, Bryce Harper, who’s primarily a pull hitter, has increased his opposite-field percentage this season, from 21 percent to 24 percent. The true change agents have been new or reassigned players. At second, Daniel Murphy has hit to the opposite field less (22 percent) than Danny Espinosa (26 percent) and Anthony Rendon (29 percent) last year. Same with shortstop, where Espinosa (23 percent) has displaced Ian Desmond (29 percent), and center field, with Michael Taylor and Ben Revere hitting less than 20 percent of batted balls to the opposite field this year compared to the departed Denard Span (31 percent). So while the Nationals spray charts are different than last year’s, it’s mostly because of changes to the roster rather than changes in batters’ approach.

As for results, well, as often happens when a player switches from pulling to not pulling or vice-versa, it’s complicated. Overall, Washington’s scoring 4.33 runs per game this year compared to 4.34 in 2015. So while the balls are landing in different parts of the field, the overall outcome’s pretty similar.

The Milwaukee Brewers: Hey Batter Batter…Don’t Swing.
Last year, the Brewers tied with the Rockies for first in the majors by swinging at 49.5 percent of the pitches they saw. This season, they’re last, swinging at 42.8 percent. They’ve gone from swinging at the most pitches outside the strike zone and the 10 most in the zone to the second fewest in both. As a result, they’re seeing more pitches: 4.08 per plate appearance, most in the majors, compared to 3.74, the sixth fewest last year.

Travis Sarandos has done a nice job of dissecting this at BP Milwaukee. There’s been a lot of turnover for the Brewers, and that’s been a catalyst for greater patience. First base has transitioned from Adam Lind (45 percent swing rate) to Chris Carter (43 percent). At shortstop, Jonathan Villar (41 percent) has taken over for Jean Segura (53 percent). At third, it’s Aaron Hill (43 percent) instead of Aramis Ramirez (52 percent). Center field’s changed from Carlos Gomez (54 percent) to Kirk Nieuwenhuis (40 percent) and one of the corners is now patrolled by Domingo Santana (36 percent) instead of Khris Davis (48 percent). But it’s not just the newcomers. Incumbent catcher Jonathan Lucroy has held his swing rate steady at 43 percent but second baseman Scooter Genett’s is down from 56 percent to 49 percent, and Ryan Braun, while moving from right field to left, has reduced his swing rate from 51 percent to 50 percent.

As Travis has pointed out, though, this hasn’t resulted in much offensive improvement. The walk rate’s up, from 7 percent of plate appearances last year to 11 percent so far this year, but the strikeout rate, in part due to called strikes on the swings the team’s not taking on pitches in the strike zone, has risen from 22 percent last year to 26 percent so far this year, the highest in the majors. Overall, the team’s TAv has risen a bit, from .251 in 2015 to .260 so far this year, and run scoring’s up from 4.04 per game to 4.13, but that’s still below average. Patience hasn’t been a game-changing virtue.

The Pittsburgh Pirates: Over the Wall.
Last season, the Pirates and Cardinals had the two best records in the majors. One of the reasons was their pitchers’ stinginess with the longball: Only 9.4 percent of the flyballs they allowed went over the fence. (The Cardinals were fractionally ahead, 9.35 percent to 9.43 percent.) This year, Pirates pitchers have allowed home runs on 13.7 percent of flyballs, trailing only the Reds, Yankees, Brewers, Rays, Twins, and A’s.

There’s an argument that this shouldn’t be overly worrisome, since HR/FB rates are generally subject to regression. That’s why the team’s FIP of 4.59 is higher than its 4.37 xFIP, which normalizes HR/FB. But the Pirates aren’t used to yielding an average number of home runs—the club was 29th in the majors in HR/FB in 2015 and 28th in 2013. However, they were seventh in 2014, suggesting that the pitching staff can weather some gopherballs. Some. For now, they’re outpacing whatever definition we might settle on for some. Francisco Liriano has allowed nine homers in about a quarter of 2016, after surrendering 15 in total in 2015. With six, Jeff Locke’s already 40 percent of the way to last year’s 15. Tony Watson’s yielded three, the same as he did over the whole of 2015. Arquimedes Caminero’s given up three too, compared to seven all last year. Some newcomers have added fuel to the fire. Jon Niese has given up 11 homers in nine starts, and batters have taken Juan Nicasio deep six times in eight starts. (Obligatory Clayton Kershaw gee-whiz stat: He’s given up 15 homers over his last 40 starts, dating back to April 2015, two fewer than Niese and Nicasio have given up in 17.) The homers are one of the reasons Pittsburgh’s given up nearly a run per game more this season than last year, 4.6 vs. 3.7. Fortunately for the club, the offense is up too, scoring 5.0 runs per game compared to 4.3 last year.

Granted, none of these trends is as interesting to follow as the Red Sox’ and Phillies’ turnarounds (or, for that matter, those of the Twins and Astros). Nor can you impress your friends by watching Ben Revere hit a groundball up the middle or Ryan Braun take a pitch and say, confidently, “Well, that wouldn’t have happened as frequently last year.” But they all play a role in where we are here in late May.

Thank you for reading

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Before anybody corrects me...Pirates pitchers have added to their gopher ball count since this was put to bed; Niese is up to 12, Liriano's got 11, and Locke has 8. Add Nicasio and they've got four in the top 26 in HRs allowed in the NL.
a much more impressive stat is that Arrieta has given up 18 HR in his last 68 starts.
Agreed, but his season is more a continuation than a turnaround.
i'm talking about the kershaw reference.
Ah. Got it.