BALTIMORE -- Adam Warren didn't pitch particularly well on Sunday, but he did pitch better than any of the three New York Yankees starters to get the ball at Camden Yards this weekend, and his start was the only game the Yankees won against the Baltimore Orioles in the series.

Among the Yankees' five starting pitchers, only Masahiro Tanaka has a significantly lower ERA than Warren's 3.78. And before Sunday's 4 2/3-inning effort in the Yankees' 5-3 getaway-day win -- an outing no doubt cut short by the humid 91-degree weather and a 29-pitch first inning -- Warren had worked into the seventh inning in each of his five previous starts.

Yet there is little doubt that Warren is in his last 10 days as a starting pitcher, perhaps even his last five. That is because Ivan Nova, who worked six tidy innings of one-run ball in a Triple-A game Saturday night, is knocking on the door of the Yankees rotation. And when the Yankees open that door, only one current starter can walk out.

Adam Warren.

Assuming all the starters remain healthy, there really is no other alternative for GM Brian Cashman and manager Joe Girardi than to send Warren back to where he came from -- the purgatory of middle relief -- the same way Girardi had little alternative other than to pull Warren with two out in the fifth inning on Sunday with the Yankees trailing 3-2, runners on first and second and a left-handed hitter, Travis Snider, coming to the plate with a chance to bust it open.

Faced with the unpleasant possibility of a sweep by the surging Orioles, Girardi did the only thing he could do, replace Warren with lefty Chasen Shreve, a move that turned out to be as shrewd as it was timely. Shreve, followed by Justin Wilson and Dellin Betances, shut down the dangerous Orioles to enable the Yankees to escape Charm City with one win out of this three-game series.

Now, probably the only thing Girardi can do is prepare to pull Warren from his rotation for good, with the exception of occasional spot starts when he wants to give someone an extra day's rest.

If you think you, and Warren, have heard this one before, you're right. Warren lost out in a competition for the fifth starter's job in spring training last year, and probably would have started this season in the pen as well had Chris Capuano not injured himself in training camp and missed the first six weeks of the season. When Capuano came back, Warren had pitched too well to be displaced, and now it is Capuano who is in the bullpen.

But when Nova returns, there really is no other move for the Yankees to make. Tanaka and Michael Pineda are the linchpins of the staff. Nathan Eovaldi is raw but has a lot of ability, and CC Sabathia isn't going anywhere, even if on merit -- or lack thereof -- he should.

So it has to be Warren, and although that will stink for him, it could turn out to be the best thing for the Yankees. Shreve, Wilson and Betances pitched excellently on Sunday, but imagine how much stronger the Yankees pen would be if Warren were available to Girardi as one more reliable right-hander to go along with Betances. Certainly, he would be a far better option than Chris Martin or Sergio Santos, both of whom performed poorly in Saturday's 9-4 loss.

And when and if closer Andrew Miller returns from his forearm strain? Then you're talking about a pen that truly shortens games and makes it a lot easier to weather the disturbing tendency of Sabathia and Eovaldi to flame out in six innings or less.

Warren in the pen means Girardi has the luxury of mixing-and-matching him with one or both of the lefties, Shreve or Wilson, to get through the sixth and seventh innings and deliver a tight game to Betances and Miller. Now that the Yankees have rid themselves of Esmil Rogers, David Carpenter and, for now, Jacob Lindgren, there no reason to watch Martin or Santos through squinted eyes. Once again, the Yankees bullpen could be an asset to the club rather than a liability.

Girardi, of course, refused to discuss the likelihood of Warren's returning to relief work after the 5-3 win.

"That decision won't be made for awhile," he said.

But it will be made, and without regard to the feelings of Warren, who has come to enjoy the life and role of being a starting pitcher.

"I've always enjoyed pitching better as a starter," he said. "I just think, especially having four pitches, trying to use all those pitches and seeing guys two, three times, four times. I think you can set hitters up and really explore the art of pitching more, whereas out of relief, it's just here's my best stuff, I'm going to try to get you out with what I've got."

And he said that even though it is obvious Nova is on his way back -- Girardi also refused to say whether Nova will make another minor-league start or be activated to pitch when the Yankees return home after playing in Miami on Monday and Tuesday -- Warren tries not to worry about what the future might hold.

"To be honest, I really haven't thought about it," Warren said. "It's just one of those things that I can't control. I just want to go out there and pitch, not think about stuff I can't control. I just take it one day at a time and see what happens, and get ready for my next outing."

Wherever that one might begin, or end.