ASHBURN, Va. — As soon as the Washington Redskins arrived home from a 27-23 loss at the New York Giants, coach Mike Shanahan phoned out-of-work tight end Chris Cooley to see whether he was fit enough to replace Robert Griffin III's top target, an injured Fred Davis.

Cooley assured Shanahan he was.

"I wasn't at home doing squats and power cleans and listening to 'Rocky' music," Cooley said Monday on a conference call with reporters, "but at the same time, I'm in good shape."

That was good enough for Shanahan. Cooley passed a physical exam and signed a contract to rejoin the Redskins, who put Davis on injured reserve with a ruptured left Achilles tendon a day after he was hurt in the first quarter Sunday.

The 30-year-old Cooley, a former Utah State University star, was released in August; injuries limited him to eight receptions and five games last season. He is a two-time Pro Bowl pick with 428 career catches, a franchise record for a tight end, over eight years in the NFL, all with the Redskins.

"I trust Chris. If he says he's in good shape, he's in good shape," Shanahan said. "So hopefully he can help us this next week."

The Redskins (3-4) play on the road against the Pittsburgh Steelers (3-3) on Sunday.

Already having played four of seven games without the player who was supposed to be his leading wideout, Pierre Garcon (right foot injury), rookie quarterback Griffin now must go the rest of the season without Davis, who leads the Redskins with 24 catches and 325 yards receiving.

"Losing Fred is huge. He's a gamer," Griffin said. "He will be missed."

Davis will have surgery today and is expected to need five to six months to recover, Shanahan said.

Before adding Cooley, the Redskins were left with Niles Paul, a converted wide receiver, and Logan Paulsen at tight end. That pair has a combined nine catches for 141 yards and zero touchdowns this season.

"He knows this offense better than anybody," Paul said about Cooley. "To have him back is going to have a big impact."

Cooley has no doubt he'll be able to play next weekend, and spending time in training camp and the preseason before getting cut made him confident he's healthy.

"I was definitely OK with not playing football this year," Cooley said, by way of explaining why he did not pursue opportunities with other teams.

He said he's "maintained the strength that I've had throughout most of my career" and done running to stay in shape and is pleased it turned out that he'll get to return to the Redskins.

"It's fortunate for both of us, I think. Fortunate for me that I get a chance to play where I want to play," Cooley said. "And fortunate for them that I sat here and waited. So it worked out."