ST. LOUIS -- The Cardinals have not yet announced a starter for Thursday's series opener in Milwaukee, but manager Mike Matheny did reveal on Monday that right-hander Justin Masterson is no longer in the mix for that assignment.
After six starts, only one of which went smoothly, Masterson will transition into the bullpen, where he'll be available as early as midweek. In his place, one of two left-handers -- Marco Gonzales or Tyler Lyons -- will draw that start against the Brewers.
"He gets it. He's a pro," Matheny said of Masterson's reaction to the shift in role. "He understands the game, understands where we are and understands where he is. But we're committed to keep working through this. Maybe this could be something that works for him."
Masterson had some success out of the bullpen with Cleveland last year, when he made three scoreless appearances for the Indians late in September. Of course, Masterson also had a strong 2013 season overall, and that has not been repeated this year.
Since joining the Cardinals at the Trade Deadline, Masterson has a 7.90 ERA over 27 1/3 innings. He's walked 11, struck out 22 and allowed an opponents' batting average of .312. In four of his six starts, Masterson allowed five runs.
While Masterson has adopted several mechanical suggestions offered by the Cardinals' staff, the club could no longer afford to have Masterson work out his issues while starting every fifth day.
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, and follow her on Twitter @LangoschMLB. This story was not subject to the approval of Major League Baseball or its clubs.