The Stuff That Dreams Are Made Of: Henry Sosa

Many popular opinions of pitching prospects are formed from general scouting reports. While these reports are invaluable resources, they can’t always be trusted. Hundreds of minor league hurlers are credited with “mid-90′s velocity,” but very few MLB starters actually have that grade of heat, for example. It’s incredibly frustrating to hear about a pitcher with “a mid-90′s heater and plus curve,” only to have him come up to the big leagues and show a fastball that averages 90.5 mph and a slider.

When a pitcher come up to the majors, we can finally get a foolproof reading on what exactly his arsenal is comprised of, thanks to the great Pitch F/X system. In this series, I analyze just that–the “stuff” of recently-promoted MLB pitchers. Now that they’ve achieved their big league dreams and thus factor directly into the MLB picture, it’s high time that we know exactly what these guys are providing.

This time, I’m taking a look at Astros starter Henry Sosa.

On July 1st, if you’d predicted that Henry Sosa would make nine (and possibly ten) starts in the big leagues this year, you’d be derided pretty heavily. After all, at the time, he was a swingman in Double-A, and he’d posted an abysmal 10.41 ERA in Triple-A earlier in the season as a reliever.

But a trade from the Giants to the Astros got Sosa, a formerly touted prospect, an unexpected opportunity to come up to the big leagues and start games. Surprisingly, he hasn’t been awful–his 4.68 ERA and 4.80 FIP point to a serviceable MLB pitcher.

Essentially a two-pitch hurler, Sosa operates with a low-90’s fastball and low-80’s slider. He works at 90-96 with the heater, averaging 93.1, and it features some nice sink imparted by the righthander’s low-three-quarters slingshot delivery. He does throw some strikes with the pitch (64.1%) and gets some whiffs (6.4%), but his location with the pitch is somewhat problematic. Here’s what he does with the fastball to righties:

And lefties:

This is a somewhat risk-averse way to use the fastball. Against righthanders, Sosa elevates the pitch somewhat, but he has enough velocity and movement on the heater that just putting it in the zone that much to same-side batters can yield acceptable results. Clearly, though, he misses badly with a number of his pitches, and seems to be in the middle of the plate at least as much as he’s on the corners, suggesting that he’s not able to really spot the pitch where he wants to. This can be attributed at least partially to his tendency to overthrow the pitch.

Against lefties, Sosa does get the ball lower in the zone, but he throws a ton of heaters way off the plate, and just about every fastball is either off the plate away or on the outer third. This is especially problematic because he uses the pitch nearly 3/4 of the time to opposite-side batters. It’s problematic enough to use the fastball that much as a starter, but even more so when batters can sit on its location as well.

Sosa’s 79-85 mph slider (average velocity of 82.3) has gone for strikes about as much as the fastball (64.3%), but has the added bonus of inducing some whiffs (14.1%). As can be expected, he uses the pitch nearly twice as much to righties (40.5%) as lefties (23.8%). Interestingly, he gets a higher whiff rate from southpaws (16.2%) than his fellow righties (13.5%). Here’s where he puts it to righties:

And lefties:

All things considered, this isn’t bad. Sosa does a credible job of throwing the breaking ball for strikes down in the zone, and also works in some plausible chase pitches. It’s no wonder that the pitch has a Pitch Type Linear Weights value of 2.31 runs above average per 100 pitches. Unfortunately, his fastball (-1.32 at over 1.5x the usage) gives all of that back.

However, the big flaw of Sosa isn’t his fastball; it’s his inability to get lefties out. He doesn’t have a changeup to keep them at bay, and while his slider has found success against lefties, it makes up just 1/4 of his offerings to them. The other 3/4, of course, consists of the exclusively-away fastballs. If lefty batters don’t pick that predictability up on scouting reports, they’re certainly bound to once they get through the lineup a couple of times in a game.

Furthermore, Sosa’s slingshot delivery means that lefties get a very good look at his ball during the windup and all the way to the plate. While his slightly herky-jerky motion may bring some deception to righties, his early presentation and fairly low arm slot are easy for a lefty batter to pick up on.

That leads to Sosa having a 3.89 FIP to righties, but a 6.47 FIP to lefties, complete with more walks than strikeouts. He also has allowed 1.53 HR/9 to lefties (small sample, but not surprising given the flat plane and lack of deception).

That’s a huge problem, and without a viable third pitch, it’s tough to see it going away. That means Sosa is best cast as a reliever in the long run, where lefthanded batters won’t have a chance to adapt to him in a second time through the order. The requisite increases in velocity with the role switch would likely apply as well, allowing Sosa to push his fastball into the 94-96 mph range with more regularity, and perhaps utilize the slider more as well. The missteps in the relief role in the minors this year certainly give one pause, but that was merely a 17-game sample, and he pitched well in relief last year. All the indications from this Pitch F/X analysis point toward a relief role being best for Sosa, and one bad stretch in that role shouldn’t be enough to override that, at least until further evidence to that effect mounts.

But, hey, a solid late-game reliever is a nice prize for an unneeded Jeff Keppinger, and the Astros could have Sosa set up Mark Melancon or even close himself. With some other starting pitchers nearing the big leagues, hopefully Sosa gets moved to his optimal role next season.

For more on the Astros, check out Climbing Tal’s Hill.

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