Miller made four starts in 2017 before a torn UCL in his right elbow led him to season-ending Tommy John surgery in May. Before going under the knife, Miller was showing the ability to miss bats at a healthy clip in his limited opportunities to pitch, and his fastball velocity jumped to a career-high 94.9 mph. Although Miller was throwing from flat ground in October, he will be less than a year removed from surgery on Opening Day. As he moves further into his rehab, a clearer timetable for his expected return should surface. The D-backs' rotation was strong despite his absence in 2017, and with all five of those starters penciled into their respective spots to begin the season, Miller could end up as the team's sixth starter and long reliever initially upon his return. The increased velocity last season makes him slightly more interesting than he was coming off of a brutal debut season with Arizona in 2016 when his ERA topped out at 6.15. Read Past Outlooks