Drafted 18th overall by the Braves in the first round of the 2011 draft, Sean Gilmartin was considered something of a safe pick for Atlanta. Gilmartin had a high floor but a low ceiling, a fast mover without projection. But for a system already holding Mike Minor and Julio Teheran, that wasn't really an issue. Four and five starters have value, especially when they're under team control. With four pitches already in his arsenal, the only concern was that his off-speed offerings develop enough to help his upper-80s fastball.
Gilmartin's fastball runs in the upper-80s and has decent movement, generating a little sink but also running in on right-handed hitters. He locates it very well, and that command makes it a nice, steady pitch, but it isn't his best offering. That honor goes to his changeup, which he'll throw to anybody at any time. It looks like a fastball but comes in around 80mph with good sink.
On the breaking ball side, Gilmartin owns both a curve and a slider. The slider is the better and more developed pitch but is rarely thrown to right-handed hitters. Instead, right-handed hitters only see the curve. It's very slow, usually in the low-70s, but in terms of quality it isn't on the same level as the slider.
In general, Gilmartin has decent control and will throw all four pitches at any time (except sliders to righties). What holds him back, apart from the lack of velocity, is that his pitches don't generate a swing-and-miss very often because there's nothing to deceive the hitter.
He's listed at 6' 2" and 180 lbs, but scouting reports I've read tend to question his size. Not that it really matters - you can pitch well or you can't.
Mechanically, Gilmartin is sound. He has long legs for his height and a repeatable delivery, with a motion that keeps him balanced and allows him to finish facing the batter. It helps him defensively, since he's in a much better neutral position by the time the batter is taking his swing. His smooth and repeatable mechanics also help him keep hitters from cheating or guessing what he'll be throwing.
Gilmartin had some minor shoulder issues this past season, which kept him on the disabled list from time to time. It was mostly shoulder tendinitis, and that seems to be what many people are chalking up his disappointing performance to for this past summer.
Braves Prospect Status
Pre-2012: Baseball Prospect Nation: 7
Pre-2012: Baseball America: 5
Pre-2013: Baseball Prospect Nation: 9
Pre-2013: John Sickels: 5
Pre-2013: Baseball America: 4
Mid-2013: Talking Chop: 10
Pre-2014: John Sickels: 15
Pre-2014: Baseball America: 10
Gilmartin is a nice pickup for the Twins, particularly for Ryan Doumit and moreso considering Doumit was owed $3.5 million dollars. While the southpaw prospect doesn't have a good deal of upside, he's a good bet to settle in well for Rochester and, quite possibly, could find himself competing for a rotation job in 2015 if he has a good season. He's going to be an interesting player to follow this summer.