Early-Season Regression Candidates Are In!

It's that time of year when we statistical analysts hope we've collected enough data to make projections about the rest of the season. It becomes particularly tempting to begin reconciling discrepancies between a player's perceived performance with his peripheral stats. So giving in to temptation, I'm going to to start with a few pitchers whose performances ought to improve a significant amount. (I also owe a hat tip to our own Nathaniel Stoltz and to Craig Glaser for their help.)

Brandon McCarthy and Vance Worley are with new organizations this year, and perhaps they have not developed a rhythm with their respective battery mates and pitching coaches. They are both cerebral pitchers that should be able to make some minor tweaks as they develop familiarity with their surroundings. Max Scherzer, meanwhile, is striking out hitters like crazy and will simply need to wait as the law of averages takes its course.

Brandon McCarthy

The idea for this topic really came when I was trying to figure out why McCarthy seems to be pitching so rotten these days. His ERA is 7.48, which is the worst among qualified starters. He's aware of it, too.

Pretty frustrated with being terrible thus far, so tomorrow I'm going to go scream at pigeons in Central Park if anyone cares to join.

— Brandon McCarthy (@BMcCarthy32) April 17, 2013

What's odd is that McCarthy's strikeout, ground ball, and walk rates are all within pretty close range of his recent norms -- and those stats are typically good early indicators of performance, as opposed to OBP and SLG. As a result, there is a monumental difference between his awful ERA and respectable 3.65 FIP (which is actually better than his 3.77 FIP from last year). That 3.84 difference between ERA and FIP leads baseball and explains how he is still at 0.4 fWAR with his league-worst ERA.

One thing that perhaps is responsible for that major gap his hefty .396 BABIP. But not having found any major differences in pitch speed, location, or selection, I'm led to believe this is largely due to sorry luck. Nor are the balls in play types worth fretting about. (His LD% is up this year, but the difference from last year is so minute – 1.4% – that its significance is statistically meaningless given the sample size.)

There's one other thing about McCarthy's 2013 numbers that caught my eye, and this one might be worth discussing with pitching coach Charles Nagy. Batters are swinging more often at his pitches and making more contact out of the strike zone than usual. His swing rate last year was about average at 45%, but it's up to 51% this year. And using the PITCHf/x strike zone, his opponents' o-contact rate is up from 70% to 82% this year. (The league average is just 63%.) Perhaps relatedly, his foul rate is up from 34% to 44% this year, and his two-strike whiff/swing is down as well.

So perhaps with some adjustments to his two-strike approach and the regressive nature of BABIP, Mac's ERA will soon reflect the fact that he is not the worst starter in the majors – not by a long shot.

Vance Worley

My own credibility is vaguely on the line with this one, as I predicted in spring training that Worley would be able to adjust to American League hitters without much difficulty. So far, however, his five starts have yielded an ugly 6.38 ERA and zero wins.

Worley, like McCarthy, has a BABIP in the stratosphere at .398. His FIP is a very sound 3.20, although a low HR/FB% pushes his xFIP up to 4.09. Still, that's loads better than his runs allowed. In fact, FanGraphs awards him 0.6 WAR with those peripherals. His GB% and walk rates are right on track, as well.

One catch with Worley so far is that he's not missing very many bats. His K% is down from 18% to 14%, and his opponents' contact rate in the PITCHf/x strike zone is quite high at over 94%. And like with McCarthy, opponents are swinging more in the zone – from 56 to 67% so far. Worley relies a lot on looking strikes – "I don’t have a lot of swinging strikes. A lot of my strikeouts are looking. That’s pretty much my deception and keeping guys off balance," he told David Laurila – so an increase in swing and contact rate might be a sign that his deception needs refining.

Max Scherzer

Scherzer is a strange early season case. He also has a mammoth gap between ERA and FIP, but in a very different way from McCarthy and Worley. Scherzer has been striking out hitters at an astronomical rate (36.2%) and keeping a low walk rate of 5.5%. His FIP is a tiny 1.65.

However, Scherzer's ERA is a pedestrian 4.02. Much of that is probably a result of his .380 BABIP (which was over .400 before his last start). He also had a staggering .442 BABIP last April, which came down to .333 for the rest of the year. And his high average this year is not based on any dangerous trends with LD%, which means it's probably just a result of bad luck.

As Scherzer's BABIP drops, his strikeout rate per inning will also drop a bit. If he was to pitch another 161.1 innings, which would give him a year-end total that is equal to his 2010–2012 averages, he'd strike out another 237 batters. However, if the rest of the year is at his career-average .314 BABIP, he will strike out "only" another 229 batters. (James Gentile has explained this brilliantly here before.)

Still, Scherzer seems to have hit a new stride in his career. If he can maintain his K/BB ratio and see his BABIP regress, Scherzer will probably wind up among the league leaders in ERA.

Editor's note: All stats shown are through 4/29