The Stuff That Dreams Are Made Of: Sandy Rosario

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 Marlins reliever Sandy Rosario.

Sandy Rosario actually got into one game in 2010, but he still remained basically anonymous to all but the most ardent prospect-watchers and Marlins fans in 2011. After all, Rosario’s resume prior to 2011 included the one MLB game and exactly one other game above Low-A. 

Rosario turned 26 in August, so he’s always been frightfully old for his levels. He spent most of 2011 in Double-A, where he put up a nice if unspectacular season. A 6 2/3 inning cameo in Triple-A didn’t go particularly well, and neither did his 3 2/3 frames in the majors (2 BB, 2 K, 5 H, 1 R).

Given that he’s been very old for his levels and that his performance has sharply declined with promotions, you might think Rosario is a finesse guy who has struggled more as he faced more advanced bats. In fact, however, he’s a pure power arm, working consistently at 93-97 mph with his fastball.

Like the last pitcher I profiled, the Astros’ Juan Abreu, Rosario’s fastball proved quite effective in his brief MLB time, inducing whiffs on five of 42 pitches and going for a strike 61.9% of the time. Like Abreu, he tends to work high:

That’s a dangerous place to live, even if you’re throwing 95. Unsurprisingly, hitters swung from their heels at the fastball when it was in the zone–just 5 of his 26 strikes with the pitch were called. He had enough gas on the pitch to induce the five whiffs (an excellent 11.9% in the extremely small sample), but unlike Abreu, Rosario saw the fastball put back in play as often as it was fouled off (Abreu had a 3/1 foul/in play ratio, which is excellent).

Rosario’s second pitch is a power changeup in the 85-87 mph range. It’s got a bit of sink but otherwise resembles his fastball, so he’s basically relying on speed differential with the pitch. Of course, when you’re setting the pitch up with a mid-90’s heater, any type of usable changeup can suffice, but the pitch doesn’t seem like it has the raw attributes to dominate. That said, Rosario clearly has confidence in the pitch, as he used it nearly a quarter of the time in his brief MLB stay, and its presence means hitters can’t just sit on the fastball.

He also throws a power slurve in the 82-86 mph range. Like the changeup, the pitch a) doesn’t have anywhere near enough data for us to gauge its effectiveness to MLB hitters and b) looks usable but unspectacular.

Rosario utilizes a fairly clean delivery that allows him to throw enough strikes, and with the exception of his very brief AAA/MLB time, he hasn’t had trouble with walks. His pure velocity should be enough to pile up some strikeouts, so I wouldn’t be surprised if he proves capable of a 2/1 K/BB ratio as a major league hurler by 2013.

The big question is with home runs. Rosario’s delivery offers little deception, and he lives dangerously with the fastball up in the strike zone. The long ball wasn’t a problem for him in the minor leagues, but hitters at the Double-A level and below are going to have trouble turning around mid-90’s heat.

At 26 and still without a bigtime upper-minors track record, Rosario remains intriguing due to his bigtime velocity, but he strikes me as less than the sum of his parts. A pitcher with mid-90’s heat, two functional offspeed offerings, and repeatable mechanics should have long succeeded in Triple-A, let alone crushed Double-A, at this age.

His BABIP figures have always been high, and I have to wonder if that’s a persistent effect. Perhaps he throws too many meatballs and his delivery makes his stuff play down?

In any case, Rosario will get a second year in the upper minors/majors in 2012, and since he’ll turn 27 in August, it’s a make-or-break season for him. There’s enough here to form a nice big-league reliever, but it’s quite unclear how close to his ceiling Rosario will get.

For more on the Marlins, check out Marlin Maniac.

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