If you knew nothing about Treinen’s 2019 season, it’s still easy to see that command played a significant issue for him. His WHIP nearly doubled, his BB9 more than doubled, and his SO/W ratio took a significant hit. He also saw a serious jump in his HR/9 rate, which is something you never like to see for a pitcher potentially heading to homerun friendly Yankee Stadium.
The most obvious reason for this regression is likely injuries. Treinen suffered through an injury-plagued 2019, first with a shoulder injury that many think affected his slider usage and then eventually with a stress reaction in his back that shut him down for the rest of the season.