Redskins Coach Joe Gibbs confirmed the worst-kept secret of the week yesterday when he said that cornerback A. J. Johnson would be activated for Sunday afternoon's game against the Miami Dolphins at RFK Stadium.

That announcement comes two days after the Redskins put Johnson through every pace and satisfied themselves that his right knee is sound. It could make for a confusing defensive backfield since the Redskins also picked up cornerback Sydney Johnson a few weeks back.

A. J. Johnson underwent reconstructive surgery on his knee only last June and was expected to miss the entire season. His recovery has been so remarkable that it may change the way doctors approach such operations.

Team doctors believe that one reason he recovered so quickly is that the operation wasn't performed until about a month after the injury, and that the knee heals better when the ligament surgery is done after all other parts of the knee have had a chance to settle down.

"He looks good," Gibbs said. "He's got enthusiasm and has really bounced around. I don't know what he'll look like when he gets in there, but right now, he looks good. It could be a boost for us."

Johnson will be used as a fourth cornerback, at least for the time being. That could mean a lot of work against the Dolphins, who typically use four wide receivers.

Injury Report

Linebacker Monte Coleman (hamstring) and wide receiver Ricky Sanders (ankle) participated in parts of practice yesterday and their status for Sunday probably won't be decided until game time. Sanders appears more likely to play, but Gibbs said of Coleman: "At this point, I'd say he'll play." . . .

Guard Mark Schlereth (ankle) also may be ready to play Sunday, but Joe Jacoby has worked at both guard and tackle this week. Ed Simmons is taking Jacoby's place at right tackle, but line coach Jim Hanifan said Jacoby could be used at any of several spots.

"We'll wait and see," Hanifan said. "Jake can handle it. You've got to be sharp at guard, but it's probably less taxing in the area of pass protection." . . . Wide receiver Walter Stanley (knee) said he'll be ready to come off injured reserve when he's eligible after the Chicago game Dec. 9 at RFK. However, running back Gerald Riggs (foot) still hasn't run much and the Redskins are saying only that they are hopeful he'll play again this year.

Bare Bryant

After catching 12 passes the first nine games, Kelvin Bryant has caught seven in the last two. He caught four for 58 yards against the Cowboys and three for 13 against New Orleans. . . . Opponents have converted the last 10 Redskins turnovers into points. . . . Meanwhile, the Redskins have scored after only three of their opponents' last eight turnovers.