Stephen Strasburg is having a good 2017, by almost every measure. Baseball-Reference’s bWAR, which is based off of runs allowed, has him at 1.5 wins above replacement; FanGraphs’ fWAR, based off of FIP, has him at 1.7; and Baseball Prospectus’s WARP, based off of DRA, has him at 2.2. All three figures are better than usual for the Nationals righty, and put him on pace for a very solid season, by his standards or the standards of almost anyone in MLB.
But beneath that even spread of WAR types lies a different sort of season for Strasburg than he’s had in the past. As I mentioned in this morning’s preview of his start tonight, his 2017 RA9 is very similar to his career mark (3.28 vs. 3.53, respectively), as is his FIP (2.82 vs. 2.85). But his process leading to those two marks is distinct from what he employed in the rest of his career. Strasburg is striking out fewer batters (24.2 percent vs. 28.7 percent career), and walking just as many, meaning the change in FIP is coming entirely from his suppressed home run rate (1.6 percent vs. 2.3 percent career).
Home run rate is usually considered something pitchers don’t have a ton of control over, as a difference of just a couple of feet can transform a routine out into a crushing blow (and vice versa). But DRA, Baseball Prospectus’s pitching metric, is designed to control for everything that can possibly be controlled for, and it thinks that Strasburg has improved substantially (2.18 vs. 2.66 career). If the lack of home runs was just a happy mistake, then falling strikeouts and stable walks would presumably translate to a worse DRA. The fact that it has instead improved suggests there’s something behind this change other than randomness. But what?
Let’s start by ticking off the things Strasburg hasn’t changed. His pitch mix has remained almost entirely steady over the course of his career, and 2017 has been no different; he’s featured the slider he introduced in 2016 slightly less, but it wasn’t a major part of his arsenal last year either.
His velocity hasn’t shifted in the slightest:
Back before the season started, Strasburg decided to stop pitching from the windup, and always pitch from the stretch, a somewhat curious decision from a starter. If it helped him achieve mechanical consistency, it’s possible to imagine the change helping his command and control. But Strasburg tried to downplay the importance of the move at the time, and it’s hard to glean any improvements from his stats: his zone rate, swing rate, and contact rate are all well within his career norms.
And if we look at the underlying contact Strasburg’s allowed, there are no obvious improvements there either. His batted ball split is very similar to his career numbers (47.6 percent ground ball rate, vs. 45.3 percent career). And his average exit velocity allowed has actually risen, from 86.7mph in 2016 to 88.1mph in 2017, as has his exit velocity allowed on balls in the air specifically, from 91.9mph to 93.9mph.
So what gives? Has anything actually changed for Strasburg? Or is the home run dip (and the strikeout dip) just the kind of thing that can happen in the first two months of the season?
Maybe. I’m digging pretty deep here, but after shittalking DRA last week, I’m giving it a lot of credit. I can’t tell exactly why it thinks Strasburg is better than he’s looked, but I’m trusting that it’s right, and not taking “ ¯\_(ツ)_/¯ ” for an answer. So while Strasburg’s overall zone rate hasn’t changed, it does look like he might be locating his fastball differently within the zone. Here is his fastball location versus righties, in 2016 and 2017:
Strasburg has moved sharply away from the low-and-away portion of the righthanded batter’s strike zone, and replaced it with more pitches up-and-in. There’s been a similar move against lefthanders; less of a vertical shift, but the same move from away to inside.
It’s possible that even a change as simple as that is behind the change in Strasburg’s approach. Inside fastballs tend to generate less whiffs than those on the outside of the plate; in 2016 and 2017, the whiff rate on fastballs over the inner third of the plate was 11.9 percent, versus 8.9 percent over the outer third. But it’s not clear that the contact they generate is weaker; the rate of extra-base hits on balls in play for fastballs on the inner and outer third is nearly equal (12.7 percent and 13.1 percent respectively). This looks like it could be an intentional shift by Strasburg, but to what end is unclear.
Not to relititgate my article from last week, but this example neatly illustrates some of my frustration with DRA. Strasburg is certainly getting different results than he has in the past, and DRA thinks he deserves credit for those changes. This page tells us that, unsurprisingly, much of that credit is coming from the weak contact Strasburg has been generating. But DRA doesn’t tell us why it believes in Strasburg’s ability to generate that kind of contact, and even a deep dive into his profile and performance doesn’t turn up much. Strasburg is undoubtedly off to a good start in 2017, but we’ll have to wait and see whether it’s a step forward or not.
Henry Druschel is the co-Managing Editor at Beyond the Box Score. You can find him on Twitter @henrydruschel.