Leone was traded to the Cardinals on Friday along with Conner Greene in exchange for Randal Grichuk.
The 26-year-old righty posted a 2.56 ERA, 1.05 WHIP and 81 strikeouts in 70.1 innings of relief in his breakout 2017 campaign. St. Louis has yet to acquire a legitimate closer this offseason, so Luke Gregerson and Tyler Lyons are the current favorites to get saves in 2018. Barring any further moves (the Cardinals have been a rumored landing spot for Alex Colome), Leone could enter that ninth-inning mix at some point in 2018 if Gregerson or Lyons struggles.