Leiter missed all of the 2019 season after undergoing Tommy John surgery last March. Given the normal 12-15 month timeline for TJ recovery, Leiter might not yet be ready to pitch even if the D’Backs did want to put him on their Opening Day roster, though he could also continue to recover and ramp up in the minors until he is ready for a potential big league return. Assuming good health, Leiter provides the Diamondbacks with a versatile depth arm who has worked as both a starter and reliever.
Most recently a member of the Blue Jays roster, Leiter (who turns 29 next month) became a free agent after the season. The righty has a 5.53 ERA, 8.4 K/9, 2.47 K/BB rate, and 48.2% grounder rate over 114 career MLB innings, all with the Phillies and Blue Jays in 2017-18. While some ERA indicators (4.37 xFIP, 4.23 SIERA) hint that Leiter’s real-world ERA is unduly inflated, Leiter hasn’t helped himself by allowing 25 home runs over his 114 frames of work, averaging out to an untenable 1.97 HR/9.