Acquired from the Red Sox in the Tyler Thornburg trade last December Pennington possesses a small frame, that can still produce double-plus velocity that will play well at the back end of a major league bullpen.

He works with a short and compact arm action from a full windup, with a drop-and-drive delivery which has some effort to it. Striking out seven over 4 2/3 innings in my viewing on August 6, Pennington demonstrated above-average ability to miss bats (9.6 SO/9 in 2017) using a plus fastball and an above-average curveball. His four-seam fastball sat 94-to-96 (T97)and while it doesn’t have a lot of movement, it does show some hop when it’s up in the zone getting hitters to chase. He also throws a two-seamer (91-to-93 mph) that shows some tail that he likes to run away from lefties late in counts. His 11-to-5 curveball has tight rotation with sharp, deep break. His changeup is below average presently (86-to-87 mph) and he lacks feel for it – it shows some tumble when thrown for a strike, but projects as average at best, even if the control comes around.

Control issues through his three pro seasons has led to a well-below-average 4.1 BB/9. A slight crossfire action in the windup causes an inconsistent release point, and his tendency is to pull pitches missing glove side. Coming off offseason elbow surgery, he’s only thrown 27 1/3 innings, but early signs point to a big improvement as he’s halved his walk totals this year to, 1.9 BB/9, and he walked none in this view.

Pennington’s elbow injury history is concerning given that he’s only only thrown 106 innings in three years. His small frame is cause for concern regarding his durability, but the upside is substantial. Due to an inconsistent third pitch, he looks destined for a bullpen role, where his plus fastball can play up. He’s got a high-risk, Role 60 ceiling if he stays healthy and keeps improving the control/command, and a Role 50 floor.