The Washington Redskins placed offensive tackle Mark May and tight end Clint Didier on injured reserve yesterday, which means they will miss a minimum of four games, and listed defensive end Dexter Manley and cornerback Tim Morrison as having a 50-50 chance of playing the season opener Sunday against the Philadelphia Eagles.

Running back George Rogers, limited by a sprained left big toe to carrying the ball only four times in the preseason, is listed as probable, which means there's a 75 percent chance he will play. If he can play, he most likely will start. A final decision is not expected until Saturday.

To replace May and Didier on the roster, the Redskins reclaimed off waivers linebacker Anthony Copeland and tight end Cliff Benson. Both were released Monday in the sort of cutdown-day maneuvering practiced often by National Football League teams.

The Redskins believe May, who has a partially torn ligament in his right knee, and Didier, who has a pulled left hamstring, will be ready to play in about four weeks. If they had put them on injured reserve Monday, before they made the 45-player roster, they would have been on the preseason injured reserve list and would have had to miss six games.

To make room for May and Didier on the roster, the team had to cut two players it wanted to keep, cross its fingers in hopes no other team would pick them up and, 24 hours after they were released, re-sign them.

That's exactly what happened, to the Redskins' relief. Both players are seen as desperately needed at the team's thinnest positions: linebacker and tight end. Benson played tight end and H-back (man in motion) for Atlanta in 1984 and 1985, where his head coach was Dan Henning, now a Redskins assistant. He was released and picked up by San Francisco, which waived him last month. The Redskins picked him up Aug. 25.

Benson will back up Don Warren at tight end and Glenn Dennison at H-back. Dennison, a former New York Jet and New England Patriot, has been a Redskin less than three weeks himself.

Copeland becomes the team's sixth linebacker, backing up Mel Kaufman at left linebacker and playing special teams. Barring further injury, the linebackers who play Sunday will be the linebackers who play the first six games, including consecutive away games at the New York Giants and Dallas Cowboys in Weeks 5 and 6.

Neal Olkewicz, who originally was supposed to miss four weeks of preseason when he injured his right knee Aug. 14, now will miss a minimum of 10 weeks all told. The Redskins could have placed him on the regular season roster and then put him on injured reserve, meaning he would miss four weeks. But they opted for the longer amount of time because Olkewicz needs more time to heal, they said.

"His injury is just so unpredictable," linebackers coach and defensive coordinator Larry Peccatiello said yesterday. "It's possible he could be ready in four weeks, but there's a stronger possibility it will take him longer. If he's well in four weeks, it will be another week or so before he is able to practice and get in playing condition. In his own mind, he is uncertain when he'll come back. He's not nearly ready yet. He just needed more time."

In Olkewicz's absence, Rich Milot, the team's regular right linebacker, will play in the middle.

"I thought Rich looked pretty good at middle linebacker this preseason," Peccatiello said. "Without Neal, we lose a competitive player who is so tough and so dependable. Everyone expects Neal to be in the middle, everyone expects Neal to make the tackle. But we know what Rich can do. I have complete confidence in Rich."

Manley, who partially tore a ligament in his right knee Aug. 8, has not yet returned to practice, but is listed as questionable (50 percent chance of playing), according to the Redskins. Morrison, who has a bruised right calf muscle and injured ankle, also is questionable. If he can't start opposite Darrell Green, Barry Wilburn will.