Lefty Hitters: The Next Frontier for Stephen Strasburg

I do feel a bit spoiled trying to nitpick Stephen Strasburg’s pitching style, when he is already one of the most dominant starters on the mound. Still, it was frustrating as a Nationals fan to watch #37 get outdueled last week by the rising Matt Harvey, who some say has stolen Strasburg’s title as "best young pitcher in baseball." And Strasburg, though still very young, has fans and analysts waiting for him now to graduate from the A-minus effort he presented last year and come into his own as the once-in-a-generation talent he is expected to become.

These lofty expectations might be unfair, but that doesn’t mean there aren’t parts of Strasburg’s game that he could improve—as he would, no doubt, admit. A couple of weeks ago I started to explored his inefficiency with pitch counts, and I’m going to dive in a bit further here. Specifically, I think Strasburg’s platoon splits are worth examining. His career FIP against righties is other-worldly (2.22), but "only" quite good against lefties (3.02).

A certain gap in effectiveness against opposite-handed hitters is common and not cause for alarm, but it may be the case that Strasburg is unusually vulnerable to platooning compared to his peers (and his overall level of performance). I’ve set up two tables below comparing Strasburg to pitchers who have demonstrated at least several years of durable, ace-quality work—a benchmark for Stephen’s next few years of work. (All data is since the 2002 season).

Comparisons

First, let us look at pitcher effectiveness, as measured by wOBA, against same- and opposite-handed hitters.

Two things stand out for me. One is that Strasburg’s wOBA against righties is superior to anyone else’s against either side of the plate. But the other is that he suffers a larger gap in performance than anyone else, which places him in the middle of the pack against opposite-side hitters.

Now let’s look at pitcher efficiency, as measured by pitches/out, with platoon splits.

Again, Strasburg has a considerably larger gap than the others. Although he is average in his efficiency against right-handers, he works remarkably harder than most others do to get opposite-side hitters out.

Given that Strasburg already owns a devastating weapon to neutralize lefties (his changeup), adding a new pitch probably isn’t the answer.

In search of a remedy

None of Strasburg’s four pitch types represent glaring weaknesses in his approach to lefties. Although his sinker is his weakest pitch overall, it actually performs comparably to his four-seamer against lefties (It’s against righties that his sinker gets smacked). His curveball and changeup are both very effective, producing opposing slugging percentages around just .250! If there is any pitch that loses the most effectiveness against lefties, it’s his four-seamer (.265 BABIP vs. righties, .375 vs. lefties). Perhaps he would be wise to ask a smart veteran like Adam LaRoche if there is something in his mechanics that makes his fastball more hittable against lefties.

Strasburg does tend to throw considerably fewer strikes against lefties. He’s at about 65% first-pitch strike against righties, but only 50% against left-handers. That’s got to change, because falling behind hitters is exactly the kind of thing that drives up pitch counts and makes hitters more selective. There’s no reason that a pitcher like Strasburg with such a dynamic repertoire can’t be more aggressive early in counts against lefties. He also ought to lower his walk rate, which is 7.8% against lefty batters—versus only 5.5% against righties (that’s 3.0/9 innings vs. 1.9/9 innings).

Like I have said before, Strasburg’s adjustments are about living up to his monumental potential, rather than keeping a job in baseball. The tweaks he makes at this stage should not be drastic, because subtle adjustments are all he needs to become the most feared pitcher in all of baseball.