3 Small-Sample Size Surprises So Far in Major League Baseball
One of the basic tenets of statistical analysis in sports is not to overreact to performance in a small sample size, and this is especially true in baseball.
With just a few games worth of 2015 data to look at, some downright wacky things have happened, like Cody Asche coming out of the gate as the game’s second most productive hitter or Nelson Cruz hitting six home runs in 38 plate appearances (putting him on a 102 home runs per a 650-plate appearance pace).
We know that Cruz won’t be able to keep up that production, and Asche’s .500/.571/.667 slash line is just the product of a cartoonish .668 batting average on balls in play.
Sometimes though, things aren’t so clear cut, and there could be other factors behind a seemingly flukey start. In the cases of slumping offensive stars Jonathan Lucroy and Robinson Cano, an atypical approach at the plate could be the reason, while the pleasantly surprising Trevor Bauer appears to be throwing a pitch both differently and more frequently to great success.
It is too early to tell whether these factors are just the products of random noise or indicative of an actual trend, but for each of them, it is worth taking a closer look.
The combination of his great bat, strong glove, and pitch-framing skills have made the Brewers catcher one of the most valuable players in the game over the past three years.
His start to 2015 at the plate, though, has been downright awful -- and not just by his lofty standards.
The 28-year-old has a slash line of .148/.258/.222, good for a wRC+ of 41. His batting average on balls in play has been on ungodly .174, but this seems to have more to do with Lucroy making weak contact then running into bad luck.
His line drive rate is 8.7% and his infield fly rate is 28.6%. Line drive rate is prone to variance, but infield fly rate tends to be more stable, as do ground ball and fly ball rate.
Lucroy’s grounder rate is 60.9%, way above his 41.6% career mark, and this partially explains why his isolated slugging (.074) is so low.
Still, even these rates need more time to become reliable, as Russell Carleton found the stabilization rates for ground balls and fly balls to be 80 balls in play (Lucroy has put 33 balls in play).
Fortunately for him, his walk rate and strikeout rate are both 12.9%, a stellar rate in both categories.
He is seeing more pitches in the strike zone (67.7% of all pitches, up from his 57.1% career rate), while swinging less overall (34.1% swing rate, down from 44.3%) and on pitches in the strike zone (52.6% versus 58.8%), according to FanGraphs.
The combination of seeing more strikes while swinging less has naturally translated into more looking strikes. 43% of the strikes he has faced have been looking, the highest rate in the National League, according to Baseball-Reference.
The results have been ugly, but considering Lucroy’s track record, it hardly seems like there is reason to panic yet, and we have him projected to slash .287/.353/.459 for the rest of the season.
Cano has been the most valuable American League second baseman of the past 25 years, but you wouldn’t know it from watching him this year.
His .211/.211/.368 slash line in 38 plate appearances equates to a 61 wRC+, though unlike Lucroy, the Mariners second baseman seems to have run into some genuinely poor ball-in-play luck.
Cano’s batting average on balls in play is .226 despite a 25.0% line drive rate and 0.0% infield fly rate, so he certainly seems to have been unlucky early on (he is hitting .375 on eight line drives, while batters hit .685 on line drives last year, according to FanGraphs).
This is not to suggest nothing has actually gone wrong for Cano this month, as his 15.8% strikeout rate is up more than four percent from his previous career average, and (as you probably inferred from his identical batting average and on-base percentage), he has yet to draw a walk this year.
Compared to his career average, the former Yankee is swinging at more pitches out of the zone (39.7% compared to 34.4%) and offering on fewer pitches inside the zone than he has for his career (67.3% compared to 72.3%).
He is swinging more as a whole but making contact at a lower percentage of these swings (80.0% compared to a career average of 86.9%). This has been driven by an especially low 60.9% contact rate on pitches outside the zone (only 27 players had a lower rate last season).
Of course, we are just talking about 129 pitches, so these plate discipline numbers are almost surely more noise than signal, even if we are using more granular data (involving individual pitches rather than plate appearances).
While we can be sure Cano’s line drives will fall for hits at a greater frequency going forward, his approach at the plate will be worth paying attention to.
Let’s finish off with a more pleasant surprise, as Bauer owns a 1.50 ERA and 2.06 FIP in two starts this season.
The Indians righty’s 38 ERA- and 56 FIP- are obviously the kind of silliness we might expect in a 12-inning sample (or from Craig Kimbrel), but is there something the 24-year-old Bauer is doing in 2015 that might distinguish himself from the guy who came into the season with a career ERA of 4.44?
While the correct answer is, “How the hell should we know? It’s a 12-inning sample,” let’s look to see if we can find anything interesting anyway.
For his career, Bauer has posted solid strikeout rates (21.8%), while walking way too many batters (11.3%), and has taken this to an extreme so far this year. His 2015 strikeout rate is a big-league leading 38.8%, while his walk rate is 18.4% (second highest in the Majors).
His first strike percentage this season (57.1%) is right around his career average (57.0%) and his total strike percentage (61.2%) is actually slightly lower than his career mark (61.6%), according to Baseball-Reference.
That explains the walks. But what about the huge spike in strikeouts?
The catalyst here is a seemingly newfound ability to miss bats, as Bauer is fourth in the Majors in swinging strikes per total strikes (per Baseball-Reference.com) and tied for fifth in swinging strikes per pitch (per FanGraphs). He also generated a 33.0% whiffs per swing ratio, according to Brooks Baseball, which would have came in second in the Majors last year if sustained for the season.
There is not enough data to see what caused this spike or if it is even sustainable, but the best guess right now is an uptick in slider usage.
According to Brooks Baseball, Bauer has thrown his slider 24.41% of the time this season, almost twice as often as last season. Opponents have swung at it nearly 52% of the time, and have missed on more than half these swings.
Last season, he generated a 23.88% whiff per swing rate on his slider, but he appears to be throwing the pitch differently in 2015. This year, his average slider velocity is 85.19 MPH, compared to 82.43 last season, and while he is getting less horizontal movement on the pitch, he is getting more vertical movement (per Brooks Baseball).
In just 12 innings, Bauer has already produced 0.5 fWAR, which is more than a third of his total value in 153 innings last year. Steamer, ZiPS, and our projections here at numberFire expect heavy regression, but it will be interesting to see if Bauer can continue to use his slider to sustain his early season success.