Sean O’Sullivan
Boston Red Sox

Fastball

54.8% Thrown  90.1 MPH

O'Sullivan rotates between Sinkers and Four-Seamers, though he relies on his straight heater to hit the zone and his riding Fastball to get grounders. Problem has been through O'Sullivan's career is his inability to locate well, allowing batters to hold career ISOs of .206 on his Sinker and a whopping .346 on his Four-Seamer.

Curveball

8.7% Thrown  72.7 MPH

While he gets a good amount of drop on Curveball, O'Sullivan rarely trusts the pitch to give it a chance of being a strong member of his arsenal.

Slider

31.6% Thrown  80.6 MPH

O'Sullivan has turned to his Slider plenty in his career, using the pitch to get strikes when he lacked the confidence in the rest of his repertoire. He increased his bend by 1.3 inches last season, getting both well above movement both horizontally and vertically. Unfortunately for O'Sullivan, he doesn't have the supporting cast to allow the pitch to get the spotlight it deserves.

Changeup

5.0% Thrown  83.3 MPH

O'Sullivan's Changeup lacks the polish to be the proper compliment to his very-hittable Four-Seamer, rendering sub 8% whiff rates in each of the last two seasons.