In his first year back from Tommy John surgery, De Leon used his changeup twice as much as he did in his previous two stints in the big leagues. The injury had an effect on its velocity, as he lost 4 mph compared to his season prior to getting hurt. However, despite the drop in velocity, he did generate six more inches of vertical drop, which helped him keep half of the batted balls on the ground. Next season, with a fresh start on a new team, he’ll look to get his changeup velocity back to where it was while still maintaining the higher vertical break.
The good news is that De Leon did not lose any velocity on his fastball after his UCL injury, and even had a lot of success with it in 2019, as he only allowed one hit while striking out five in 10 at-bats. Being accurate definitely had an impact on its success, as he threw 65% of his heaters for a strike.
De Leon has never used his slider much, so it comes as no surprise that in his first season back from Tommy John surgery, he only threw it two times. Unless he makes some big offseason changes, don’t expect him to utilize it more than usual in 2020.