"There is no exact timetable. It's hard to put concrete dates on anything, because you just don't know. You are starting to feel better and that is a good sign," Zimmerman said. "I've been doing a few rehab things. There's really nothing you can do right now."
Zimmerman said he is not going to rush to get back on the field. He said the chances of reinjuring the hamstring if he rushed back are sky high.
"For as hard as it is, you have to think about the future," he said.
It appears that Anthony Rendon could be the Opening Day third baseman next season, and Zimmerman has already said Rendon is the best man for the job. If that's the case, Zimmerman could be the starting first baseman, but that's not certain given Adam LaRoche having a mutual contract option for 2015.
Zimmerman can also play left field. He has looked comfortable while playing 26 games there this season.
Asked what position he would like to play next year, Zimmerman said, "That's going to be a conversation that I will have with [general manager] Mike [Rizzo], [manager] Matt [Williams] and the other guys who make that decision. You want to help them out the best way they can to construct a team. It's hard to think about next year with the way this team is playing and how exciting the season has been. I think there are considerations to be thought about. I think it's unfair to talk about that stuff when there is something so special [going on]."
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time. He also could be found on Twitter @WashingNats. Daniel Popper is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.