After missing 3 1/2 weeks because of inflammation in his right rotator cuff, Nova beat Tampa Bay in his return on Sept. 15. Since then he is 0-1 with a 9.00 ERA in two starts, allowing 11 hits and four walks in seven innings.
"I'm sure he's disappointed. But that's OK, too. This is a game where you have to be productive on a consistent basis," Yankees manager Joe Girardi said Monday. "We still have him in our plans, but right now he's just struggling a little bit."
Nova is 12-8 this season, down from 16-4 last year. He knew the move was possible given the way he was throwing.
"If I have to pitch out of the bullpen, I will do it," he said.
Phelps is a 25-year-old rookie who learned he made the big league roster on the final day of spring training. He is 4-4 with a 3.34 ERA in 10 starts and 22 relief appearances, including a 1-1 record in starts against the Red Sox. He didn't get a decision in his last start, against Toronto on Sept. 19, and has pitched out of the bullpen twice since then.
"It's a big deal," Phelps said. "I want to pitch in big games. They don't get a whole lot bigger than down the stretch in a pennant race. ... It just shows they have faith in me pitching a big game."
Girardi wouldn't say whether he would use ace CC Sabathia on three days' rest if the Yankees wind up playing Thursday and Friday. New York, which clinched a playoff berth Sunday, began its closing series against Boston tied with Baltimore for the AL East lead.
If the Yankees and Orioles remain tied, Andy Pettitte would start Thursday's tiebreaker game at Baltimore for the division title.
A Yankees' loss in that would send them to the new one-game, wild-card playoff on Friday. Girardi would have to decide between Phil Hughes on full rest or Sabathia on short rest, with the other pitcher then in position to start the opener of a best-of-five division series if the Yankees got that far.
"Let me worry about these three before I have to make that decision," Girardi said. "We have people lined up to make starts. So, I mean, we got to just see where we're at."
New York started its full complement of regulars for the first time in more than three weeks, with Mark Teixeira batting fifth and playing first base.
Teixeira injured his left calf Aug. 27 and returned Sept. 8 at Baltimore but aggravated the injury diving into first base on a game-ending groundout and had not played since.
"It feels a lot better than when I came back the first time in Baltimore," he said. "There's always going to be tightness until I sit down for a month."
Teixeira, hitting .255 with 23 homers and 81 RBIs, played two intrasquad games and a simulated game last week at the team's minor league complex in Tampa, Fla.
"It was like the Bombers vs. the Yanks, or the Pinstripes vs. the Bombers," he said. "The Yankees always, they won every game. It's good to see that. The standings were undefeated down there."