Rondon is working on improving his changeup in spring training, MLB.com reports.

EDGE Analysis

Rondon used primarily fastballs and sliders to post a 2.97 ERA and strike out 45 batters in 36.1 innings last year. He threw his changeup just 3.4 percent of the time last year, and Rondon called it a "so-so" pitch. If he can improve his changeup, Rondon could post even better numbers in 2017 with a solid three-pitch mix.