Negative Differences in K-BB% with Men on Base: Alex Cobb

Chris Cwik’s piece on Tyler Skaggs and the tough times the southpaw has endured while men are on base prompted me to wonder about that aspect of pitching. Which hurlers have performed differently, at least in terms of some typically advanced statistics, after hitters have reached base? What might we ascertain from what we discover?

Generally, when a pitcher pitches while men are on base, we assume that he works from the stretch. Therefore, if a starter is considerably less effective after a hitter has reached base against him, we may hypothesize that the hurler struggles while he pitches from the stretch. However, that isn’t necessarily true, because the pitcher may do things such as change his pitch mix in order to achieve a different type of result against a future hitter. Still, we can begin to make conjectures.

A snapshot of data like this can be misleading, so it’s important not to draw concrete conclusions. But we may discover a lede or six, a thing or a half-dozen that we wish to explore further. We may stumble upon a buy or sell candidate for fantasy baseball players. Or we may not find much of interest. We may just scratch our heads some more. I do enough of that without the presence of baseball information.

Now that I’ve qualified this thing, let’s get on with a reckless claim.

Name	Bases Empty					Men on Base					K-BB% diff
	TBF	HR/9	K%	BB%	K-BB%	TBF	HR/9	K%	BB%	K-BB%
Alex Cobb	225	0.68	26.2%	5.8%	20.4%	148	1.25	14.2%	8.8%	5.4%	-15.0%
Marco Estrada	314	1.95	22.9%	6.7%	16.2%	168	2.41	13.7%	10.1%	3.6%	-12.6%
Matt Cain	234	1.15	22.2%	7.7%	14.5%	140	1.51	12.9%	10.0%	2.9%	-11.6%
Tyler Skaggs	256	0.72	21.9%	6.3%	15.6%	170	0.67	10.6%	6.5%	4.1%	-11.5%
Francisco Liriano	196	0.65	26.0%	8.7%	17.4%	194	1.16	21.7%	15.5%	6.2%	-11.2%
C.J. Wilson	290	1.11	24.5%	7.9%	16.6%	201	1.05	17.9%	12.4%	5.5%	-11.1%
R.A. Dickey	377	0.99	21.5%	6.9%	14.6%	221	1.71	15.8%	11.3%	4.5%	-10.1%

I’d been optimistic that Cobb would have a nice turnaround after the All-Star break. He might still, and a 3.76 ERA isn’t terrible. But I hadn’t realized how much he’s struggled while men are on base. His batted-ball data in those situations isn’t much different from that of those with the bases empty. In his last two seasons, in which some fantasy owners have liked him as something close to a potentially undervalued ace, his K-BB% was around 10% with men on base, but that mark has dipped noticeably.

What’s the cause? I’m not sure. But it’s conceivable that the oblique strain that forced the Tampa Bay Rays’ pitcher to miss a month and a half early this season has either lingered and affected him while he’s pitched from the stretch or prompted him to be cautious in that scenario. The more distance Cobb puts between himself and that injury, the better off he’d seem to be. But health issues, whether structural or soft-tissue, can affect players long after they return to action, perhaps for the balance of a season.

Cobb’s start on Wednesday versus the St. Louis Cardinals seems to be encouraging. He didn’t walk anyone, however. He allowed two hits in an inning once but was aided by a caught stealing. When the Cards’ leadoff man reached with a double in the sixth frame, they proceeded to hand the right-hander an out with a sacrifice. Then a fielder’s choice grounder allowed the Rays to throw out the runner who was going from third to home. What might have happened had St. Louis just decided to swing away instead of to lay down the bunt?

It’s hard to say whether Cobb will continue to perform this way while men are on base. The news isn’t immediately encouraging. He spoke earlier this month of his attempts “to get his mechanics right,” as Marc Topkin put it. Mechanical issues sound like a possibly prime reason for struggles from the stretch. Cobb wondered aloud if he hadn’t put enough time into them before he returned to action. Topkin covered the subject again prior to Cobb’s then next start, noting that the righty let an inning get away from him in his previous outing and in general has been unable to get deep into games.

Perhaps the All-Star break has given Cobb the proper time to heal. His owners wouldn’t mind hearing that he didn’t do much more than play catch with his extra four days between starts. A rebound is surely still possible, but latest information suggests that, even if one is likely, it might not be as strong as I’d hoped.