"While Nationals third base Ryan Zimmerman did not rule out a return by the end of this season, he said he wants to make caution a priority with his injury and seemed mostly resign to finishing as a spectator, vowing not to play unless his strained rib muscle heals completely.

"I wouldn't say it's all the way done yet," Zimmerman said. "I'm working every day to see if I can rehab and get back out there. We're just being cautious. We don't want to come back a little bit too soon and hurt it even worse. I'm getting better each day. I'm trying as hard as I can to get back out there for a few more."

Zimmerman, who turns 26 tomorrow, said his injury - a strain to the intercostal muscle on the right side of his midsection - typically takes anywhere from one to two weeks to fully heal. He first started feeling the strain six days ago and played for a one game with it aching. He felt improvement today for the first time, but nowhere near enough for Zimmerman to not sit out a fifth straight game.

"We're not going to rush anything," Zimmerman said. "You want to have no pain at all. Under the circumstances that we're under, there's really no reason to go out there or take pain medicine or do something like that to play. To get out there and play, it would have to be 100 percent better with no risk to hurt it.

"There's no reason to go out there and risk it. It's frustrating. You always want to finish the season with these guys. We've been together the whole time, and we've been through some tough times. Obviously, I want to finish with these guys. It's tough."

Zimmerman wants to sit out for two reasons. First, he believes Alberto Gonzalez gives the Nationals a better chance to win than he does while playing with diminished health.

I didn't think I was going to be as good as Gonzo out there. If I'm going to go out there and play at 75 percent, it's not worth it for me or the guys in here. That's one thing I've always said. It's not fair to them or me if I'm out there and I can't help them win.""