The Cubs sent lefty Randy Rosario to Triple-A Iowa prior to Sunday’s series finale against the Diamondbacks. Taking his place in the bullpen is right-hander Alec Mills.

Mills will probably see some action in today’s game, as Tyler Chatwood is getting the start for the Cubs. Joe Maddon made the tweak in the rotation because the Diamondbacks hit worse against RHP than LHP. Yet, Chatwood will only be around for 75-80 pitches. So, expect Mills to come in for a couple innings after Chatwood.

As for Rosario, he might not be back in the Cubs bullpen for a while. Fellow lefties Mike Montgomery and Xavier Cedeño are rehabbing down in the minors and may be close to returning. So, Rosario could just end up being the odd man out when they’re ready to come back.

As for Mills, he had a 4.00 ERA in 18 innings with the Cubs last year. He has started one game for Iowa this season, allowing one run in four innings.