The Diamondbacks begin play today with a major-league worst 4-11 record and are already six games behind the first-place Dodgers in the National League West, so they have decided to shake things up their starting rotation.

Jack Magruder of FOX Sports Arizona reports that the Diamondbacks will move the struggling Trevor Cahill to the bullpen. Mike Bolsinger has been called up from Triple-A Reno and will make his first major league start Saturday against the Rockies.

Diamondbacks manager Kirk Gibson hinted last week that Cahill’s spot was in jeopardy, so six runs (two earned) on five hits and five walks over four innings yesterday against the Dodgers was apparently the last straw. The 26-year-old right-hander is 0-4 with a 9.17 ERA and 13 walks over 17 2/3 innings this season.