Sodo Mojo’s Top 40 Seattle Mariners Prospects: 15-11

Brandon Williamson may be the pitcher with the best chance to become a #1 starter in the system, but the path to reaching that scenario is extremely low. Williamson has a few more warts than the pitchers ahead of him on the list, but there are some tantalizing tools to work with.

Williamson’s arsenal includes a fastball that touches 96 MPH and sits comfortably in the low 90’s. Williamson’s long 6’6″ frame helps the pitch play up and he backs up the hitter with two solid breaking balls. The slider is ahead of the curveball and is a true out pitch, but the curveball shows flashes of plus-grades with good shape and depth.

Williamson has a fringy changeup that will need to improve to reach his ceiling, but it is usable in certain situations. Williamson is a good athlete who throws from a 3/4 arm slot with average or slightly above-average command.

In order to max out his potential, Williamson will need to find a way to carry his upper-90s velocity more consistently, improve the changeup a half grade, and stay on top of the ball more consistently to help improve his command. While these aren’t easy things to do, they are all things that he has already shown flashes of, giving him a higher probability to reach his ceiling than most.

As he is now, Williamson’s floor is that of a high-leverage left-handed reliever. Williamson will likely start 2020 in West Virginia. He is a bit further away from his 2019 draft counterparts George Kirby and Isiah Campbell but may pitch ahead of them in the big league rotation when he arrives.