Detwiler, 25, will join other young starters Brad Peacock and Tom Milone as pitchers the Nationals want to look at for the remainder of the season. The Nationals, five games under .500 and 11 games behind the Braves in the wild card standings, can use the final two months to break them in.

“It’s not that I don’t like Gorzelanny,” Johnson said. “Gorzelanny doesn’t have anything to prove to me. But if we were fighting for a pennant, we’re not going to do. But because we’re where we’re at, we’re going to look at some young arms, give them an opportunity to kind of establish.”

Detwiler, the sixth overall pick in the 2007 draft, has some major league experience, having made 20 career starts and 10 relief appearances. He had been serving as a left-handed long reliever for the Nationals, allowing two earned runs in 10 innings over five appearances. Johnson felt like Detwiler had earned the spot in the rotation opened by Jason Marquis’s trade.

“He’s a good young arm,” Johnson said. “He’s pitching awful good. He’s done a good job out of the ‘pen. We had high hopes on him. He’s very poised out there, makes quality pitches. He had a great spring training. By all accounts, he probably should have made the club out of spring.”

The Nationals will have another opening in their rotation in a matter of weeks. Jordan Zimmermann, who today helped the Nationals to a 3-2 win over the Mets with six scoreless innings, will be limited to only four more starts because of a 160-inning limit placed on him because this is his first full season after Tommy John surgery.

Johnson suggested Zimmermann could physically handle more than the predetermined limit – “he might be in the best shape of anybody I’ve got on my staff,” Johnson said. He may try to revisit the innings limit with General Manager Mike Rizzo, but Johnson does not expect the innings limit to change.

Stephen Strasburg will also take up a rotation spot once he returns from Tommy John surgery, which could happen as soon as early September.