Zimmerman, who suffered a Grade 3 hamstring strain in July, started to feel sore on Saturday. He tripled to right field in the seventh inning against the Marlins, and coasted into third base without any problems. However, Zimmerman ran hard to the plate on a Wilson Ramos chopper and was thrown out. It turned out that Zimmerman may have pushed himself too hard on that play, because he felt sore afterward.
On a scale from 1 to 10, Zimmerman said the hamstring is "a seven or an eight. 80 percent."
"He pushed it beyond where he has pushed it. After the game he said, 'You know what, it's a little bit sore,'" Williams said. "So we gave him Sunday, we gave him yesterday [off]. I can't run him out there without putting him through some tests. He took early grounders. He will do a full [batting practice], run around, potentially run some bases, just to make sure, because I don't want to throw him back in there and have it not be right."
This week is important for Zimmerman as far as determining what his role will be during the postseason. Williams already announced that Zimmerman will play three positions -- third base, first base and left field during the season's final week.
"We'll find out this week what I can do and what I can't do," Zimmerman said. "From there, we'll figure out what my role is going forward. No one really knows. Matt doesn't know, I don't know, [general manager Mike Rizzo] doesn't know. The reason we tried to get back to this point so quickly was so that we can assess the situation and see where we are at."
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the Time. He also can be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.