MMs Top 25: #17 LHRP Jack Leathersich

#17 LHRP Jack Leathersich (LR: #13)

Bats: L Throws: R
Height: 5' 11" Weight: 200 lb

Age: 24
Acquired: 2011 Rule IV draft, 5th round, University of Massachusetts-Lowell

2014: (AA/AAA) 3-3, 1 SV, 3.31 ERA, 54.1 IP, 15.4 K/9, 4.6 BB/9, 1.362 WHIP
2013: (AA/AAA) 4-0, 3 SV, 4.63 ERA, 58.1 IP, 15.7 K/9, 6.9 BB/9, 1.646 WHIP
2012: (A/A+) 2-6, 2 SV, 3.00 ERA, 72.0 IP, 14.1 K/9, 4.0 BB/9, 1.153 WHIP
2011: (SS-A) 0-0, 1 SV, 0.71 ERA, 12.2 IP, 18.5 K/9, 2.1 BB/9, 0.711 WHIP

     When you are a senior draftee out of College and have already made the full time switch to RP....the margin of error you have to reach the MLB is so thin. A pure reliever needs to show an unbelievable talent to generate outs to not only beat out 7 other peers per level, but to also beat out the 5+ rotational guys who still have the option to make the switch. For the Leather Rocket, he's done everything right so far except one thing....conquer Las Vegas.

     Leathersich has had two shots at AAA so far and both times he went from an unstoppable force to a free pass giving machine. His 61 game career in AA has resulted in a 2.63 ERA, a K rate of 16.0 per 9 innings and a manageable 4.4 BB per 9 IP. his 39 game career in AAA has produced a dreadful 7.23 ERA, 14.7 K/9, and a 8.9 BB/9 rate. We all know the jump from AA to AAA is tough but the split in his BB/9 rate is just absurd. He's also given up twice as many HR's in half as many games. So what the heck is going on? In a Q & A session with Fangraphs' David Laurila, Leathersich alluded to what he thought the problem was...

"The guys you play against at the higher levels are much better hitters and much more patient. I’ve learned that you need to command the strike zone. That’s what I struggled with in Triple-A this past year. The hitters have a better sense of the strike zone and aren’t swinging at borderline pitches, so you need to command your pitches and get ahead. I’ve always thrown high in the strike zone, and I’m working on throwing the ball down and then climbing up the ladder when I need to."

     There's the problem, despite having below average fastball velocity, Leathersich still loves to use the upper half of the strike zone. This allows his deceptive delivery to be that much more effective as his "slower" fastball and get on a batter quickly. Here's where we drop some Science on everyone....In humid environments, the air is actually lighter than normal dry air. That's because H20 molecules are lighter than the O2 and N2 molecules found in normal air. This causes less "drag" on a baseball allowing it to travel farther in flight and in Leathersich case....stay up rather than gravity dragging the pitch down. So every time Leather Rocket is trying to climb the ladder, the pitch goes too high and is a ball....every time he aims low in the strike zone, the pitch stays up right in the batters wheelhouse. If you don't have natural side to side movement, like Noah Syndergaard does, it's almost like you have to "aim" to throw a ball down in order to get strikes.....something that is awful to do for development purposes.

     Because of this phenomenon, I personally think Leathersich is a candidate to jump straight from AA to the MLB. Make no mistake, he's MLB ready right now. The only thing preventing him from being on the team is the fact that despite being a Lefty, he actually carries reverse platoon splits and is more effective against right handed batters. He'll be second in line, behind Cory Mazzoni, to replace anyone in the MLB bullpen in case of injury.

Ceiling: MLB High Leverage Strike Out Machine RP (Brad Boxberger)

Floor: MLB Medium Leverage Strike Out Machine RP

Anticipated Assignment: (AAA) Las Vegas Bullpen.