A shrug was the only answer David Phelps gave at first. The soft-spoken right-hander did not want to discuss how valuable he has become to the Yankees' pitching staff. He did not want to talk about how he could find himself in the starting rotation if Ivan Nova – who pitches tonight against the Arizona Diamondbacks – or Phil Hughes suffer through another poor start. But when something goes wrong, the Yankees call on Phelps to bail them out, no matter the situation. Long relief. Middle relief. Starting. Even if the second-year pitcher doesn't want to talk about it. "Right. I, um ... I'm fortunate that I've had success in all those roles," said Phelps, after realizing his shoulder gesture did not satisfy the question. "The more valuable I can make myself, the more roles I can do, I'm happy to do that." Phelps, 26, again has emerged as the Yankees' most valuable – or at least their most flexible – pitcher. But his versatility may be his biggest obstacle to starting. And the Yankees (6-5) need him in a flexible role more than ever. Andy Pettitte's 40-year-old body already has forced the team to twice push back his next start. Hughes still struggles to keep the ball in the ballpark. Nova remains an enigma, unable to piece together consistent outings. And when someone fails, Joe Girardi calls on the 6-foot-2, 200-pound Phelps. The manager did so last season when Phelps posted a 3.34 ERA in 99 2/3 innings. He started 11 games and came out of the bullpen in 22 others.