Murphy hasn't been in the Nationals lineup since Saturday in Atlanta, when he appeared to hurt himself running the bases. He did take two pinch-hit at-bats during this week's series in Miami, but would have been replaced for a pinch-runner had he reached.
The Nationals hoped a couple days off would suffice for Murphy, but his leg didn't improve, so they sent him for an MRI, which revealed what Baker called a "mild" strain. They want him to avoid any running or other baseball activities that could affect the area through the weekend, after which they'll evaluate him again and decide a course of action.
"We're going to shut him down," Baker said. "He'll probably sneak in to hit somewhere. Especially if, like he said, it doesn't hurt. We're just trying to stop him from various activities."
If they clinch the National League East title - they enter play tonight with a magic number of two - the Nationals would open the postseason two weeks from today. The club isn't making any predictions yet on how much time he'll need to return without fear of aggravating the strain.
"I'm not a doctor. I don't know," Baker said. "They're doing everything they can to try to alleviate the pain and get rid of whatever's in there. We have some very capable staff here. I'm glad he didn't do it any worse. That's why we didn't put him in a situation where he had to run. But now we're not going to put him in any situation, to make sure he doesn't have to run."
The Nationals are hoping they caught the problem quickly enough and have kept Murphy from doing anything to make it worse. While it looked like the strain happened as a result of one play on the basepaths, Baker suggested it may have built up over more time.
"Usually you don't really do it on one play," the manager said. "It's a progression when your legs are getting tired. And Daniel, like we knew in the beginning, he's a legs person, whether it's playing defense or offense. So we just feel fortunate that we pulled the plug when we did."
Veteran infielder Stephen Drew, who only recently returned from a long DL stint with an inner-ear condition that caused vertigo-like symptoms, will start the first two games of this weekend's series at second base. Baker said he'll start someone else for Sunday's finale against the Pirates.
Given their overwhelming lead in the division, the Nationals can afford to give Murphy time to heal.
"That's big," Baker said. "Cause what if we need to push him? And even if he got there, would we lose him for the whole playoffs? I'd hate to see life without Daniel and life without (Stephen Strasburg). Those two are big horses. Fortunately for us, we got Drew back when we lost Daniel."
Strasburg, by the way, threw off flat ground again today. The Nationals have yet to suggest a timeframe for the right-hander (out with a strained flexor mass in his elbow) to start throwing off a mound.
Reliever Sammy Solis, meanwhile, threw off the bullpen mound today for the second time this week. The left-hander, out since August with shoulder inflammation, is slated to do it again Sunday, after which the Nationals will decide whether he's ready to face live hitters.