WASHINGTON -- The result could cost him some time on the mound, but right-hander Jason Jennings demonstrated during one play on Wednesday night why he has emerged as the leader of the Rockies pitching staff.

Jennings had thrown five innings. Coming to the plate in the sixth, just one batter after JD Closser's two-run homer had given the Rockies a lead, Jennings singled. The next batter, Cory Sullivan, bunted, and Jennings made a hard slide into second base. On that play, Jennings is believed to have sprained his right middle finger, and he had to leave the game.

The Rockies held on for a 3-2 victory (Jennings' ninth of the year) and their first road series win this season, but are unsure if Jennings will have to miss his next start.

But what has won the Rockies over is Jennings' toughness. His only concern at the time was taking out Nationals shortstop Jamey Carroll and preventing Sullivan's misplaced bunt from becoming a double play.

Jennings said that he will have an X-ray or an MRI performed by team physicians on Thursday.

"It's not my personality to peel off and not slide," said Jennings, whose hand was caught beneath the bag. The middle and ring fingers bent backward, with the middle finger taking the brunt of it.

"He got hurt tonight because he's playing hardball," said manager Clint Hurdle. "He's trying to break up a double play. You can't fault a guy for that."

Jennings gave up three hard hits in the first inning but escaped with just one run scored, and rebounded to finish with two runs and four hits against him in five innings. He struck out three and walked none, thus continuing a positive stretch.

After starting the year 1-6 with a 7.05 ERA in nine starts, Jennings is 5-3 with a 3.49 ERA in his last 11 outings. The injury cost him a chance at his seventh "quality start" (six or more innings, three or fewer earned runs) during the current span. He hasn't ruled out making his next scheduled start, on Monday at home against the New York Mets.

"I got hit on the elbow with a line drive my rookie year and made my next start," he said. "Hopefully, it's a little bit better tomorrow. As long as I can throw one bullpen [session], then I'm fine. I can pitch my next start."

The Rockies have come to the realization that they're better when they can depend on Jennings once every five games.

They had been willing to listen to offers for Jennings, feeling that a former No. 1 draft pick and former National League Rookie of the Year could bring a bevy of top-notch players. But more and more club officials are treating Jennings as an ace and saying privately that he isn't going anywhere.

Jennings, who signed a two-year, $7 million contract last winter, has said on a couple of occasions that he didn't know if he'd be with the team beyond the July 31 non-waiver trading deadline. But on Wednesday he said he believes that the organization is beginning to look to him as a leader. Nonetheless, he wants to earn that status.

"They haven't told me anything one-on-one, but that's not something I think they would do," said Jennings, who is 49-43 in 124 career starts, all with Colorado. "I think them giving me the ball the first game back [after the All-Star break] is their way of showing me. It was an honor. I hope I hold up my end of the bargain.

"I'd like to be the leader. It's something that doesn't happen overnight. But for the teammates, coaches and organization, I'd like to come out and earn that respect."