Arizona Fall League Pitch F/X: Sean Gilmartin

The Atlanta Braves have been somewhat conservative with their selections in the MLB Draft the past several seasons. But what that strategy has done for them is give them a multiplicity of major league quality players, especially pitchers. Add lefty Sean Gilmartin to that list. Gilmartin will not wow you but he will be a major league starter and a somewhat above-average one pending complete disaster. Today we’ll see how he will make that happen.

The scouting report on Gilmartin entering the draft was that he was a lefty with excellent polish and great control. His fastball in the 88-91 MPH range was a solid pitch with late run towards right-handed batters and he also threw a nice slider and decent slow curveball, but his best pitch was a changeup that he sold extremely well with his arm action and which also featured late sink and horizontal fade. We are lucky enough to have some Pitch F/X courtesy of Brooks Baseball on Gilmartin from his time in the Arizona Fall League, and let’s see how the data compares to this scouting report we have on him. We’ll display this data using one of my original Pitch F/X graphs.

  (For a general explanation of the topic of Pitch F/X and specifically how to read this type of graph, please click here.)

In this data set, GIlmartin was able to get his fastball consistently up to 91-92, and if he could keep it there, it will help him out quite a bit. GIlmartin’s fastball features run towards righty batters and solid sink, and even if it isn’t a plus pitch since it won’t ever force a lot of swings and misses, he commands it well and it’s definitely more than average. As long as Gilmartin can hit spots with his fastball, he should be fine. The main thing about Gilmartin’s fastball is that it sets up his true plus changeup. It looks like his fastball out of his hand both in terms of arm speed and movement before disappearing thanks to excellent late sink and some fade towards right-handed batters. It’s a pitch that will force manifold whiffs and groundballs as long as he can set up well with his fastball. Gilmartin’s biggest problem with his changeup is that when his fastball has been ineffective, he has used it too often and even if hitters will swing and miss at it once or twice in a row, eventually they’ll stay back on it and hit it hard.

Gilmartin’s slider was an effective pitcher for him in this sample as he was able to get nice late downward movement on it and control it well to force swings and misses. The problem for Gilmartin with is slider is that he releases it from a different release point compared to his fastball-changeup combination and he also has struggled at times to command it. Gilmartin’s slider flashes plus at times, but other times he will hang it and it will be hit hard. Gilmartin’s other breaking ball, which Pitch F/X identified as a curveball, was really a softer slider with bigger downward break. It completely perplexed hitters just because of the magnitude of its descent as it approached the plate, but Gilmartin could not locate it for a strike. If Gilmartin can ever learn to control his “curveball,” it could pair well with his slider and be an effective pitch. What was interesting about Gilmartin’s bigger breaking ball was that he threw it out of the same arm slot as his fastball, which gives me the impression that he’s trying to get rid of the difference in release point between his breaking ball and fastball, which would make his entire arsenal play up.

Gilmartin has quality stuff and all he needs to do to be ready for the big leagues is learn to control and command his breaking balls better and maybe get some more movement on his fastball. As a Rays fan, Gilmartin reminds me of a lefty Jeremy Hellickson with his fastball, plus changeup, breaking ball combination, with the big differences being that Hellickson’s pitches, specifically his fastball, have better late movement and he also features better control than Gilmartin. But Gilmartin has the ability to be an impact starting pitcher even in a Braves system that features quality starter after quality starter. Gilmartin’s lack of a dynamite fastball is somewhat annoying, but he has the great secondary pitches to overcome it. Expect to see Sean Gilmartin in a Braves uniform before long, and he has the ability to be a good major league starting pitcher.

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