McWilliams was all projection when the Phillies drafted the 6-foot-7 righty as a rail-thin high schooler from Tennessee in 2014. Since then, he has wound up a part of two different trades, moving to the Diamondbacks in 2015 and the Rays in a mid-season swap this season. A loaded Rays farm system created a 40-Man Roster crunch this November, leaving McWilliams unprotected from the Rule 5 Draft as a first-time eligible player. Kansas City scooped him up in the Major League Phase, so McWilliams is set to join his fourth organization by the age of 23.
The fastball sits in the low-90s, able to reach back for 95-to-96 mph when he needs it. McWilliams’ height gives excellent natural extension, racking up an above-average amount of swings through his fastball for its velocity. The ball takes a lively late hop that rides up and armside when he elevates with intent. Command within the zone is the last aspect of his fastball McWilliams needs to develop, as he’s still learning to coordinate his extra-long levers down the mound. Despite historically solid walk numbers, he often center-cuts his fastball and will need to find a way to angle to the lower-third more consistently against big league hitters. A mid-80s slider is his primary off-speed, grading as a fringy offering right now given its short one-plane action. McWilliams flashes more depth on the pitch at best, hinting there’s room to find an average breaking ball in time. He mixes a little-used changeup at 84-to-86 mph, still fairly uncomfortable with it.
There’s a lot to like here, and if you squint hard enough, McWilliams’ size and chance for three pitches could make him a #5 starter if he improves his command and changeup. Even if he doesn’t, the two-pitch mix and track record of limiting walks gives some floor in relief–perhaps with the ability to throw multiple innings given his experience as a starter.