DENVER -- Carlos Beltran's first game on a rehab assignment went at least as well as hoped for from the Mets' perspective.

Beltran's performance as the designated hitter for Class A Brooklyn on Wednesday -- 1-for-3 with a walk and an RBI -- was secondary to the way he felt after getting back in game action for the first time in 10 weeks, though Beltran's postgame comments revealed some anticipated soreness that comes from a combination of being out of commission for so long and the general state of ballplayers physically by the time September rolls around.

"I'm not 100 percent, but no one in baseball plays at 100 percent right now," Beltran said, according to Mets vice president for media relations Jay Horwitz.

Beltran did not note any specific pain related to the bone bruise in his right knee that has had him sidelined since June 22.

"When they're talking pain and soreness, I think they're talking in general about the body," assistant general manager John Ricco said before Thursday's series finale with the Rockies. "They're not talking specifically about the knee. If we hear anything about the knee, that's going to be a big red flag. When a guy doesn't play for as long as he didn't play, it's going to be natural that he goes out there last night and runs around a little bit and feels sore. That's what we anticipate."

Beltran started in center field for the Class A Brooklyn Cyclones on Thursday and played five innings. He fielded four balls and went 0-for-2, while walking, grounding to second and flying to center in Brooklyn's 5-4 loss to Hudson Valley.

"How he felt today will determine what he does tonight, whether he DH's or plays in the field," Ricco said.

Reports from Brooklyn have Beltran determined to get back to a competitive level before the season ends, and Mets manager Jerry Manuel has been happy with what he's heard.

"When I read the report, it said he feels good," Manuel said. "He played. To me, that's progress. How he responds to that today, and then plays five innings in the field -- how he responds to that, that's progress. But after every time out, I think there's an evaluation that goes into that. You decide whether or not you continue to go forward, or you say, 'Hey, maybe not.' We would have to all be on the same page."

The Mets are confident that the medical evaluation approving Beltran as fit to play and the self-evaluation from Beltran can guide them to an appropriate path as the season winds down.

"The word from the doctors was that he was cleared to play, and unless something comes up that he needs to see the doctor again, there's no plan [to stop his rehab]," Ricco said. "Clearly, we're monitoring it on a daily basis for any red flag at all. This has been, for months now, monitored pretty closely, and conservatively. That's not going to change."

Beyond that, Ricco is leaving questions of Beltran's baseball fitness to the four-time All-Star.

"The ball's in his court as to how he feels," Ricco said. "The skill part of the game, getting his timing back -- that's really in his court. As long as the physical [aspect] continues to be fine, it's going to be totally on him as to whether he feels he can come back and compete."

Also on the health front, Manuel confirmed his doubts that Gary Sheffield would be able to play in the field again this season, given the back issues he's been experiencing since leaving a game with spasms on Aug. 26.

"It's going to be tough," Manuel said. "I'm not getting good reports on his back. The type of hitter he is, too, it might take some time."

Sheffield said after Wednesday's game that he was not currently available to pinch-hit, but he was optimistic that he was improving and that he would see more action in some capacity before the season ends.

"It's a possibility that he could pinch-hit, but it would have to be a last resort type of thing, an emergency type of thing," Manuel said Thursday. "We'll continue to check with him on a daily basis and see how he is."