Another rookie reliever is on his way to Chicago, as the Cubs today called up lefty pitcher Scott Maine from AAA – and promptly deposited Justin Berg in Iowa to take his place. Maine, 25, was acquired from the Diamondbacks over the Winter in the Aaron Heilman trade, and has worked his way through the Cubs system this year, putting up a 3.12 ERA as a reliever between two levels.

As for Berg, he struggled in his second stint with the Cubs in 2010, leaving his season ERA at a disappointing 5.77. He’ll be back in September, and will get another shot to make the pen next year.