Baker is in the rotation because Yu Darvish is on the disabled list with mild inflammation in his right elbow and may not pitch again this season.
The Rangers are still expecting Derek Holland back in the rotation in September. Holland, recovering from offseason knee surgery, is scheduled to pitch Thursday for Triple-A Round Rock on what is his last start on medical rehabilitation assignment. The Rangers plan to activate him and put him back in the rotation when the rosters expand in September.
T.R. Sullivan is a reporter for MLB.com. Read his blog, Postcards from Elysian Fields, and follow him on Twitter @Sullivan_Ranger. This story was not subject to the approval of Major League Baseball or its clubs.