The Chicago Cubs have seen their lead in the National League Central shrink to just half a game, and they’re hoping for a boost from their newest pitcher as Cole Hamels was added to the team’s roster Sunday.

Hamels, who was acquired in a trade with the Texas Rangers, is slated to pitch on Wednesday night when the Cubs play the Pittsburgh Pirates at PNC Park, and joined the team in St. Louis on Saturday.

To make room for Hamels on the 25-man roster, the Cubs optioned pitcher Cory Mazzoni to Triple-A Iowa.

The Cubs have already done some shuffling to clear out a spot for Hamels in the starting rotation, announcing that Mike Montgomery will retain his spot in the rotation and that Tyler Chatwood will be demoted to the team’s bullpen.

The Cubs will wrap up their series against the Cardinals on Sunday night, with Kyle Hendricks taking the ball for the North Siders.