We haven't seen Jameson on a major-league mound since July of 2023, as he eventually required Tommy John surgery in September of that year. The expectation is that he will be ready to roll on Opening Day of this season, and the Diamondbacks plan for him to operate in a relief role. Jameson came up through the minors and broke into the majors as a starter, but he had been pitching in relief before his elbow blew out and was having success. Prior to the injury, Jameson reached the upper-90s with his fastball with regularity while also showcasing a wipeout slider. He could be a potential closer if things break right, but there are unknowns with Jameson in 2025 in regard to how his stuff bounces back from surgery and what his usage will look like. Read Past Outlooks