What happened: The Pittsburgh Pirates are calling up right-handed pitcher Antwone Kelly from Triple-A Indianapolis to join the major league roster. Kelly, 22, has hit 100 mph on his fastball 17 times this season and recently transitioned to a relief role in preparation for his debut.

Why it matters: The promotion provides a power boost to a Pittsburgh Pirates bullpen that has struggled with a 4.45 ERA this season. Kelly was added to the 40-man roster last winter and will look to stabilize the late-inning rotation as the team fights for position in the NL Central.

What to watch: Kelly is expected to be available for the start of the three-game series against the Miami Marlins on Friday.