Arrington had a tear in the lateral meniscus of his right knee. He'll be on crutches for a week and will be re-examined in a week. Typically, these surgeries often sideline players for two to four weeks.
Arrington was fine Wednesday morning, but his knee swelled up later that night and he was sent to Dr. James Andrews in Birmingham, Ala. Andrews is a senior consultant to the Redskins' medical staff.
''Yesterday was the best the knee looked,'' Redskins coach Joe Gibbs said. ''Sometimes with those things, it just swells up. We felt like it was better to go ahead and get them to look at it.''
Arrington played with a bad knee against the Giants.
He'll be replaced by Lemar Marshall, in his third year with the Redskins. He'll be making his first career start, as will be Ron Warner at defensive end. There's a chance that Mike Barrow could return to the middle, bumping Antonio Pierce into Arrington's spot.
The 6-foot-2, 230-pound Marshall was cut by three teams before sticking with the Redskins in 2002.
''Those are some big shoes to fill,'' Marshall said. ''But I'll just go out and play my game. I can't play how LaVar plays. I have to play like Lemar plays. It rhymes, but that's what I got to do.''
In other Redskins injury news, quarterback Mark Brunell did not practice and Gibbs said, as of right now, he's planning on Patrick Ramsey starting Monday. But that could change if Brunell improves.
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