"His throwing program changed a little bit in the winter, coming off some shoulder problems last year they rested him a little bit," Yost said before Wednesday's game. "He didn't do quite as much long toss. We talked to Robby today and he's got no answers for it. Nobody does. He's fine, he feels good, he's just dropped 6 miles per hour off his fastball and we've got to find a way to get that 6 mph back."
For now, Yost plans to use his young pitchers, including right-handers Aaron Crow, Jeremy Jeffress and Kanekoa Texeira, and left-hander Tim Collins in late-inning situations.
"We're not even two weeks into the season and I haven't set defined roles but, yeah, Collins has been throwing good, Crow's been outstanding, and Jeffress will be in more of those situations," Yost said. "Texeira has been solid all year except for one outing, so we're fine."
Yost stayed with Tejeda despite the diminished velocity through his first seven appearances. But, after Tuesday night's loss, his ERA had risen to 5.06 and opponents were hitting .417 against him.
"As a guy who's been a mainstay in your bullpen, you still have to give him the opportunity to fail," Yost said. "Even though you're concerned with the velocity, if he's getting guys out, you maintain his role until something like that happens, and then you have to make adjustments."
Tejeda and closer Joakim Soria were the only two bullpen pitchers assured of jobs when Spring Training began.
"I have no doubt that Robby will get his velocity back," Yost said. "He just has to get it back."