The Cubs could soon be down to Carlos Zambrano and four rookies in the starting rotation. "Instead of flying with the Cubs from Milwaukee to Denver, the club sent [Mark Prior] to Chicago to have team physician Stephen Gryzlo examine his shoulder," reports the Chicago Tribune's Paul Sullivan. One of those rookies will be Juan Guzman, who will be recalled to start Saturday's game, reports MLB.com's Tony DeMarco.

Prior had a shoulder problem at the beginning of the season that ultimately shut him down for two-and-a-half months. Unfortunately, I was right to expect a less than successful return for Prior this year from that injury.

Guzman has a 5.68 ERA in 25.1 innings with the big league club this year. He has a 4.04 ERA in 75.2 inning with Iowa, with a 3.2 K/BB ratio. Before being sent back down to Iowa, he sat on the big league bench for more than two weeks after a good 5.1 inning relief appearance on June 16 against Detroit.