Washington Coach Joe Gibbs said it reminded him of last season, so productive was the Redskins' offense in the first half of Friday night's 27-23 preseason victory over Cincinnati at RFK Stadium.

Gibbs was relishing the performances of quarterback Joe Theismann, who threw two touchdown passes in his first half; running back John Riggins, who ran seven times for 41 yards in one first-half drive, and Mark Moseley, who kicked field goals from 40 yards and 44 yards.

In a less pleasant sense, though, Gibbs also might have been talking about wide receiver Art Monk, who is blessed with ability and seemingly cursed by injury. In the final regular-season game last season against St. Louis, Monk broke a bone in his right foot and missed the playoffs and the Super Bowl.

Friday night, it almost seemed like last year for Monk: he sprained the medial collateral ligament in his right knee while making a 19-yard reception in the first quarter. He returned for one more play, then the pain forced him to stop.

Monk will be out from 10 days to three weeks, team doctors say. The season opener is Sept. 5 against Dallas--22 days away.

"Obviously, it will be pretty much the same as last year if Art isn't there by Dallas," Gibbs said yesterday after watching game films with his assistants. "Either Alvin (Garrett) or Virgil (Seay) would have to fill in.

"But I guess I'm optimistic. I'm taking it for granted as a mild sprain and I'm told he'll be out from seven to 10 days."

"There isn't much swelling, which is good. We'll know more in a couple of days," trainer Bubba Tyer said yesterday from the team training camp in Carlisle, Pa. Monk drove two hours north to Carlisle to receive treatment yesterday before returning home (the Redskins did not practice).

"I'm just a little disappointed about it. I've never had this type of injury," Monk said late yesterday. "I don't think it's that major of an issue. I'll be ready by Dallas. No doubt about it."

Monk leaped for a pass from Theismann and, as he came down, cornerback Ken Riley hit him in the back of his knee. The collision bent Monk into a contorted position, making him seem like a 6-foot-3, 209-pound pretzel.

"He just hit me when I came down. I felt a little pain," said Monk, who started training camp one month ago at the slow pace of one practice per day before participating in two-a-days for the past two weeks. "I guess not many people go through this game without ever getting hurt."

If Monk's present state is glum, it merely matches that of Richie Petitbon, coach of the Redskins' defense.

"Nobody played well. The whole (defense) played bad. We have to attack more. It was a miserable effort. How's that for a rosy report?" said Petitbon.

The Redskins' defense yielded 330 yards, or 6.2 yards per offensive play. Cincinnati quarterback Ken Anderson worked over the secondary, completing 11 of 14 for 155 yards and one touchdown in the first half.

Although strong safety Ken Coffey, a first-year player, was involved in a game-high nine tackles and got his second interception in two preseason starts, Petitbon was not pleased with his effort. Coffey, 23, is playing Tony Peters' position since Peters' arrest on a cocaine charge.

"We can't win with that kind of performance. (Coffey) just got beat. His coverage was lacking," Petitbon said. "The thing we can't lose sight of is that he has never played this position before and we must be more lenient . . . But if he's not ready, we'll have to take the necessary steps."

One possible defensive alteration coaches have discussed is moving Curtis Jordan, a reserve free safety who also intercepted a pass Friday night, to strong safety. Jordan is a seven-year NFL veteran.

Petitbon also said he was displeased with the play of LeCharls McDaniel, who splits time at left cornerback with top draft pick Darrell Green. This position usually is filled by Jeris White, but the 10-year veteran is unsigned and is holding out. Redskins officials expect Green to start at left cornerback against Dallas, assuming White has not returned and no purposeful trade can be made.

"LeCharls had a very bad game. Darrell did some good things, but he is in the same category as Coffey: a lot of learning to do," said Petitbon.

"We felt that the defense dropped off this week and the offense and the special teams both picked up," said Gibbs, adding of the defense, "You do get down, but I think they played very well last week (in a 13-10 overtime loss to Atlanta). I think that's a very good (Cincinnati) offense they went against."

Apparently, evaluation of reserve quarterback Tom Owen's performance Friday was a difficult subject for coaches to discuss yesterday. Owen played the second half, completing five of 11 passes for 46 yards. He threw one interception. The Redskins' only three points of the second half were set up by Jordan's interception at the Cincinnati 35 early in the fourth quarter.

"We'll have to wait and see," is all Jerry Rhome, the quarterback coach, would say of Owen.

Asked about Owen's performance, Gibbs paused long enough to call 10 audibles before saying cautiously, "I think it's a careful evaluation with quarterbacks. We've got to see Babe (Laufenberg, rookie quarterback from Indiana) in a game still . . . It had been a while since Tom had played. My idea is that it will go down to the end with our (reserve) quarterbacks."