In late December, after the Chicago Cubs had reportedly – but not yet officially – agreed to terms with free agent starting pitcher Edwin Jackson, I had only one small concern with the signing. I liked the term and I liked the rate. I liked the age of the pitcher, and the caliber of his stuff. I liked his durability, and I liked the role he filled on a team that was going to need him over the coming years. But I was a touch nervous about the slight decline in velocity Jackson saw in 2012, and I examined whether, if it was a permanent decline, Jackson was going to soon drop in effectiveness. The conclusion? Eh. Maybe. But maybe not. Who knows. It was one of those kind of things. There aren’t always firm conclusions.
But, here we are in early May, and Jackson is really struggling. His fastball velocity – an average of 94.5, 94.4, and 94.7 MPH in 2009-11, and 93.4 MPH in 2012 – has dropped further still, down to 92.7 MPH. With Jackson giving up more than 10 hits per 9 innings this year, are we seeing a confirmation of those velocity-related fears?
While that might yield a neatly-packaged narrative, I’m not so sure just yet.
To be sure, if you get past the small sample of just 38 innings – which you can’t really get past, because the’s entire point of “small sample size” (it means the sample is too small to draw any meaningful conclusions) – Jackson’s baseball card stats look pretty grim. He’s got a 6.39 ERA and a 1.632 WHIP, and just two of his six starts have been quality starts (at least 6 IP and no more than 3 ER). Win/loss as a stat is often useless and misleading, but you could argue that Jackson has earned his 0-5 record.
But when you dig a little deeper, you see a guy who is striking out more batters – 9.24 per 9 – than he ever has in his career. He’s also inducing far more ground balls than he ever has before. His 54.7% ground ball rate blows his career mark (44.1%) out of the water, and is in the top ten in all of baseball. His FIP (3.21) and xFIP (3.55) put him right around 30th in baseball, and second best among the Cubs’ starting pitchers, behind only Jeff Samardzija (Jackson’s xFIP is just a touch behind Carlos Villanueva). In other words, the advanced stats say Jackson hasn’t just been “not bad,” he’s been affirmatively good.
So, what’s up, then? Why is he giving up so many runs if he’s pitching so well?
Mostly there are two things informing Jackson’s poor performance, and each is arguably the product of mere bad luck: an unusually high BABIP against, and an unusually low LOB%. The former, BABIP (batting average on balls in play), is an indicator of how many balls a pitcher allows the batter to hit into play that are falling in for hits. For the most part, BABIP is not correlated with actual pitching ability, which means when it gets far too high – as Jackson’s .353 mark is this year (.307 career) – it’s often a fair guess that the guy is just suffering some bad luck. The latter stat, LOB%, is the rate at which a pitcher is stranding runners on base. For Jackson this year, nearly every other guy who reaches base is also scoring, as his his LOB% is a frighteningly low 52.3%. His career average being 70.9%, you would have expected Jackson to have given up a great deal fewer runs this year than he has, simply by chance, and even while giving up close to the same number of hits.
When you combine a high BABIP and a low LOB%, there’s a compounding effect: you’re allowing more base runners than the fairness overlords dictate you “should” be allowing, and you’re allowing more of them to score than you “should” be allowing.
The short, non-number version of all of this: Jackson’s been pitching all right, and he’s been pretty unlucky.
This is not to exonerate Jackson entirely, or to suggest that he hasn’t had some issues. Although the balls finding the grass is largely a fluky product of vagaries of a batted ball, the more line drives you give up, the more likely you are to give up more hits. And Jackson’s been giving up line drives at a 22% rate this year, higher than his career average of 19.9%. That’s going to drive up your BABIP against, and could be the product of some lost velocity. For another thing, Jackson’s giving up too many walks – 4.26 per 9, which is both far too high and much higher than his career average (3.6).
In the end, you could argue that Jackson has been slightly less effective this year than in years past, and you could argue that a decline in velocity and shaky control are to blame. Anecdotally, I don’t think I would blame you. But, given the small sample, and the advanced stats, I also think you could make a pretty strong argument that, on the balance, Jackson has actually pitched well. He’s giving up far more hits on the balls that are put in play than he likely will going forward, and he’s actually doing a good job of reducing those balls in play by way of the strikeout.
Going forward, you would expect regression in Jackson’s BABIP against and his LOB% (the good kind of regression), and, assuming he keeps throwing the ball well, it will suddenly appear as though he’s “figured it out.” That will especially be true if he cuts down on his walks.