Ogando, 29, has already been on the DL on two other occasions this year. He missed three weeks with biceps tendinitis in late May and more than a month with right shoulder inflammation from early June to mid-July. A groin strain sidelined him for a month last season.
In 15 starts around the injuries, Ogando has gone 5-4 with a 3.47 ERA and 1.31 WHIP in 80 1/3 innings. He has bounced back and forth between the rotation and bullpen in recent years, perhaps contributing to the arm problems.
Blackley, 30, had a 4.89 ERA in 35 relief innings for the Astros earlier this year. Texas acquired him last week, and he was able to make one start for its Triple-A affiliate before being called up.
Right-hander Matt West was transferred to the 60-day DL to clear a 40-man roster spot for Blackley.