Adam Warren is 5-5 with a 3.86 ERA in 15 starts at Triple-A and will make his Major League debut on Friday against the White Sox.

The Yankees were hit with a double-whammy of injuries to left-handers CC Sabathia and Andy Pettitte on Wednesday, but general manager Brian Cashman said that his preference is to search for answers within the organization before burning up the telephone lines looking for potential trades.

Sabathia (left groin strain) should be back in the Yankees’ rotation after the All-Star break, missing just two starts, but Pettitte (fractured left ankle) is expected to miss six to eight weeks.

“I would prefer not to go outside,” Cashman said. “Obviously if we do go outside, we’ve done that before. This is part of the process. You have to have alternatives; this gives opportunities for people to step up. Just like some guys in the bullpen have allowed us to step up and withstand some injuries – that’s what Boone Logan, Clay Rapada and [Cody] Eppley have done – we’re going to have to ask for some other guys to do that for the rotation, as well. Let’s play it out and see where it takes us.”

The Yankees have already assigned starts to Adam Warren and Freddy Garcia, and Cashman said that David Phelps could soon be promoted from Class-A Tampa, where he is building back into a starter.

Phelps threw 55 pitches in his last outing at Class-A and could throw 65 to 70 pitches next time. Cashman said that Phelps would have been the first choice if he was ready to serve as a starter, but since he isn’t, the call will go to Warren.

“Warren is by far the next best for us. He’s earned it,” Cashman said. “He almost earned the opportunity last year, too. We’re excited to get a chance to see what he’s got to do. I know this is a day he’s been dreaming about and growing for. Throw strikes, try to eliminate the butterflies, trust the guys he’s got behind him and we’ll see where he takes us.

“He’s earned the right and he’s due for the opportunity. Now it’s going to come, which is great. Whatever happens is going to happen in the short-term; it’s not going to change the fact that we believe he’s a big-league starter going forward here at some point on a consistent basis.”