The Phillies lack electricity in the limbs of their system. Out of the four pitchers in last year’s Baseball America Top 10 list, only one (Ethan Martin) had a consistently plus fastball (Morgan, Biddle and Pettibone were the others). While the Phillies young arms are not exhilarating, hard throwing pitchers are becoming more prevalent in the league as a whole. This season, about 120 pitchers who threw 30+ big league innings this year had an average fastball velocity over 92mph (according to FanGraphs’ page and pitch type classification which can be pretty shitty. It says Jake Diekman’s fastball averaged 91mph this year. That’s not right.) compared to roughly 90 pitchers with 60+ grade fastball velo in 2008. That’s a very unscientific 33% increase in half of a decade and only serves to make the Phillies system look more barren than it is at first glance. There are as many plus-plus or better fastballs in the entire Phillies system (Ethan Martin, Kenny Giles and prospect du jour, Juan Sosa) as you might have seen in the Buffalo Bison (Toronto’s AAA) bullpen on a given night this season (Jeremy Jeffress, Brad Lincoln, John Stilson). That’s not to say some baby dragons in the GCL or Williamsport won’t breath fire one day as they fill out and mature, it’s just the present reality.
So if Juan Sosa is one of the hardest throwers in the entire system, why haven’t you heard of him? Well because he’s just that, a thrower. I’ve seen the fastball up to 97mph and sitting 94-96mph with arm side run. It’s a true-plus-plus pitch but Sosa’s command of it is spotty. His variant arm slot alters plane and causes it to flatten out at times and he’ll get hit as a result. Sosa flies open with his front foot, his arm comes through late at times and in general he just doesn’t repeat several aspects of his mechanics well. It’s below average command and control.
The secondary stuff is pretty interesting, too. There’s an average slider in the 82-84mph range that Sosa will add and subtract to and from while changing his arm angle once in a while to show a different shapes on the pitch. I’m not a fan of the latter. The slider has two plane movement but it’s not explosive vertically or horizontally, instead it’s a little loopy and slurvy. His use of the pitch is a bit immature but it’ll flash plus. So will the changeup which is a firm offering in the upper-80s with some run and improving arm speed. This is the pitch that has the most projection and the one I’m most intrigued by. Right now it is fringe average and I project it to solid average, but if you wanted to argue that, as Sosa fills out and gains control of his currently slight body, his feel for the ball will improve enough for the changeup to become plus, I could see that.
I just don’t have the confidence that that physical growth and the feel for the change that comes with repetition will ever come. Sosa turns 24 years old this week and he’s listed at 6’2”, 165lbs. I would have liked to have seen some of that physical development occur by now. Instead, Sosa looks like he’s made of angel hair pasta. I think the Phillies might have a middle relief piece here if a few things improve and maybe even more than that if some sort of pitching coach warlock can shape and mold this very real talent. But buyer beware. We’ve seen pitchers with more velocity and similar secondary stuff fall short of expectations before (Scott Mathieson, Phillipe Aumont is doing it now, Casey Weathers, etc.) but there’s too much arm strength here to dismiss. Sosa is Rule 5 eligible this winter and I think he’s a no-brainer 40-man roster add.