The Redskins moved to strengthen their pass rush at left end today by acquiring 12-year veteran Tony McGee from New England, where he had been the leading sacker for the past seven years. In return, New England received a conditional late-round 1984 choice.

McGee, 33, became expendable in wake of the progress made by the Patriots' Kenneth Sims, the first player chosen in the 1982 draft.

The relatively inexpensive price Washington had to pay for McGee, who is no all-pro but still is considered capable, made it unnecessary for the Redskins to include kicker Mark Moseley in the deal, as had been under consideration.

New England is having field goal problems and still might be in the market for a kicker. But any trade for Moseley will not be made, if at all, before this weekend, after the Redskins can judge rookie Dan Miller's performance against Cincinnati in Riverfront Stadium tonight in the final preseason game (WJLA-TV-7, 7:30 p.m.).

"McGee gives us some of the things we need (at end)," Coach Joe Gibbs said about McGee, whose nickname is "Mac the Sack."

"He's a guy who has proven he can do it. He has a great motor and he's a gung-ho guy who will chase the ball all over the field. He'll hustle for you. He's been a starter in camp this summer and he's had a good camp."

The Redskins aren't expecting McGee, who will be used solely on passing downs, to become another Fred Dean because of the uniform change. But the situation at left end was becoming desperate. Mat Mendenhall was handling early-down running chores adequately, but they were getting no pass rush from either Mendenhall, John Lee or Mike Clark on passing downs, even when they went to special situation defenses.

"I feel great about the trade," said McGee, a Bishop College product who has 93 career sacks, including 13 1/2 in 1977 and six last year. "I'm looking forward to coming to Washington. I've had a pretty good camp but when you draft a guy like Sims, you can't expect to sit him on the bench . . . Everyone knows he's going to play. This is best for myself and for the Patriots."

Defensive Coordinator Richie Petitbon said the trade "probably should upgrade us at left end, but we'll have to wait and see how McGee plays. He looks like he still can rush the passer. But the search (for end help) still isn't over."

To make room for McGee, the Redskins waived tackle Garry Puetz, a former Patriot.

Gibbs said he hoped McGee would be able to play some against tonight. Both the Bengals and the Redskins are 0-3 in preseason.

The Redskins are viewing this game as a final examination for all the players who are fighting for spots on the 49-man roster, which will be announced Monday. Gibbs said he still is looking for a cohesive effort even if he makes a lot of substitutions.

"I'm sure Cincinnati will make this close to a real game effort as they can," he said. "That will give us a chance to evaluate our people against a Super Bowl team."

Quarterback Joe Theismann will start, but Gibbs said he plans to use both Bob Holly and newly acquired Tom Owen "although I reserve the right to change my mind." Other positions will also be under close scrutiny:

Running back. Wilbur Jackson will start and do the bulk of the ball carrying as Gibbs tries to determine who will back up John Riggins now that Joe Washington is injured. Gibbs said Otis Wonsley and Clarence Harmon also will play. Riggins, resting a bruised knee, will not.

* Wide receiver. Art Monk will see limited duty, so Charlie Brown, Virgil Seay and Alvin Garrett can play more. Seay remains the starter opposite Monk, but Brown could come on with a good game. Garrett fell off with a so-so performance last week against Buffalo.

* Tight end. Don Warren, who is set, won't play much, if at all. Rookie Mike Williams, also a roster lock, will share time with Rick Walker at one tight end spot while Rich Caster and Clint Didier divide up time at the other. Both Walker, who did not have a good 1981 season, and Caster, who wasn't expected back from a knee injury, have played better than anticipated, complicating the squad cut. Didier, despite promising potential, could be the odd man out unless he does well in this one.

* Utility. Is there a place somewhere on the roster for Terry Metcalf? Metcalf, who has had no contact work since recovering from an offseason concussion, finally will get a chance to play. He'll be used on special teams and perhaps at both receiver and running back.

* Kicker. Miller will do all the place-kicking and might share some of the kickoffs with fellow rookie Jeff Hayes. If Miller flops, the Redskins will have to reevaluate this position, where Moseley has lost considerable ground since camp began.

Much like Washington, Cincinnati has been plagued by turnovers which had left Coach Forrest Gregg livid. Even so, the Bengals still feature the same cast of players who nearly beat San Francisco in the last Super Bowl.

Gregg had announced that he will play his regulars for much of the game, including quarterback Ken Anderson. Cincinnati also has been strengthened by the improved play of last year's No. 1 draft choice, receiver David Verser, the heir apparent to Isaac Curtis.