Randy Thomas said he'll miss at least six weeks after undergoing surgery on a torn triceps tendon on Wednesday.
Thomas will likely miss more time after the six-week period as he rehabs from the surgery.
The team still has not indicated whether Thomas will remain on the active roster or be placed on injured reserve.
It's possible that Thomas could be back for the stretch run in December.
"I want to be there," Thomas said. "But even if it doesn't go my way, I'm still going to be around. Guys know I'm going to be around."
Said head coach Joe Gibbs: "We're still going to get together with the doctors and get a final analysis on it. We'll probably talk to everybody and get a roundtable discussion on that one, just to see exactly what they think [on how long Thomas would be sidelined]."
Thomas had the surgery, which reattached the tendon to the bone, on Wednesday morning at Reston Hospital Center.
Thomas was at Redskins Park in the afternoon, visiting with coaches and teammates.
He said that his arm will be wrapped in a cast for six weeks, and then he can begin a rehab stint.
"Actually, I'm [feeling] positive today," he said. "The last couple of days were tough. You can't question what happens. You just have to try to get better and recover."
Thomas suffered the injury in the first quarter of Monday night's 20-12 victory over the Philadelphia Eagles. He was replaced by Jason Fabini.
Thomas is uncertain how the injury happened.
"That's a good question," he said. "I do what I always do. This time I hit a guy--I think I hit him hard--and he returned. He hit my arm, and I guess the tightness of the muscle just gave."
Thomas said he has spoken with Jon Jansen, who is sidelined for the season after undergoing surgery on an ankle injury last week.
"He told me, 'We'll be rehab buddies,'" Thomas said.
-- DANIELS, SMOOT BACK AT PRACTICE
The Redskins returned to practice on Wednesday to prepare for this Sunday's game against the New York Giants.
Defensive end Phillip Daniels and cornerback Fred Smoot both participated.
"Phillip took quite a bit of work," Joe Gibbs said. "Smoot took some work."
Daniels and Smoot sat out Monday night's victory over the Philadelphia Eagles. Daniels has a foot injury and Smoot has a hamstring injury.
Said Daniels: "I expect to play this week. I'm going to go out and practice this week and see how it feels. I won't give you a definite go, but as the week progresses hopefully I'll feel better and get a chance to play."
Defensive back Vernon Fox, who also missed the Eagles game due to a groin injury, did not practice.
-- O-LINE SIGNING COMING SOON?
Redskins coaches and personnel officials worked out several free agent offensive linemen on Wednesday morning.
As of Wednesday evening, the team had not signed a player.
"We worked out some guys," Joe Gibbs said. "We're doing our research and our homework. We haven't made any decisions."
Coaches are looking to add a veteran offensive lineman to provide depth in the short term, and possibly the long term.
With Randy Thomas sidelined for this Sunday's game against the Giants, but still on the active roster, the Redskins would have just seven offensive linemen available to them.
-- MOSS FAMILY REUNION
Redskins wide receiver Santana Moss is the older brother of Giants second-year wide receiver Sinorice Moss.
It's the second time the two brothers will compete against each other; they were on opposite sidelines in last year's Redskins-Giants regular season finale. The Giants won that game 34-28.
"My family, they'll be rooting for both of us," Santana said. "I can't really tell you personally who they want to win, because I don't get into all of that. I just know my mom and dad and my aunt--they come to every game. They'll be behind both of us.
"We'll have the same family support we've always had, and we'll just say to each other, ?I hope the best man wins.'"
Santana is tied for the Redskins' team lead in receptions with nine catches for 117 yards. Sinorice does not have a reception yet, but he does have a one rush for four yards.