Last Sunday, after Dallas repeatedly ran around his right side linebacker spot, Monte Coleman felt as if he had become one of those fishing holes he loves to find on a warm summer's day.

"You know, the kind that you keep going to because the fish never stop biting and you know you are going to be successful," said Coleman, the Redskins' physically gifted third-year pro. "Well, Dallas found out I was a real good fishing hole. They kept coming back again and again."

Coleman laughed. "I decided I didn't want to be anyone's fishing hole. After the game, it was the worst I've ever felt. I didn't know what to do."

With a little help from the Redskin coaching staff, Coleman thinks he will recover from his depression in time for Sunday's 1 p.m. game at Buffalo (WDVM-TV-9). Washington (5-7) would profit greatly from an improved performance by the man it hoped would become its big-play athlete this season.

This is a vital game for Buffalo (7-5), which is 6-1 in Rich Stadium this year. The Bills are only a half-game out of first place in the AFC East, but are on the road the last three weeks of the season. The Redskins' longshot playoff hopes would be extinguished by a loss here.

"We need turnovers', said Richie Petitbon, the Redskin defensive co-ordinator, whose unit will be facing the league's third-most productive offense despite 33 turnovers."Buffalo is going to move the ball on us, they are going to gain yards. For us to stop them, we have to force mistakes. If not, we could be in trouble."

Of all the Redskin defenders, Coleman is most blseed with the physical assets needed to cause opponents' mistakes. Yet, instead of playing up to his potential this season, he has struggled, first because of a fractured shoulder and then because of mental hangups about playing on the right side.

He has had only one interception (after making two in preseason), one sack and one fumble recovery all year, much less than he had to produce for the Redskin defense to hold up against superior offensive personnel. He also is third in tackles with 67, far behind leaders Neal Olkewicz (159) and Mark Murphy (141), both former free agents.

The Redkins finally decided early this week that something had to be done to ease Coleman's mental anguish. So they made what might seem to be only a subtle change, moving him from the right to the left, where he played in training camp.

But to Coleman, it was as if he suddenly was doing the fishing, not his opponents.

"I didn't go in and demand to be moved," he said, "I had made up my mind that if I had to stay on the right, I'd forget everything that happened and start playing well.

"But playing the left feels so much better. I'm much more confident. I've made up my mind that I'm going to play the best game of my career against Buffalo.

"I just wasn't playing well at all on the right. I felt so low I could do pushups on a dime. I was violating the basic rules of linebacking, I wasn't containing on my side. I felt uncomfortable, nothing was coming naturally. I wasn't being physical enough. I was thinking instead of reacting."

Coleman's troubles started in the second game of the season, when he hurt a shoulder and had to sit out four weeks. He still wasn't healed completely when he returned, but the Redskins had so many injury problems at linebacker he felt he was obligated to play as soon as he could.

By then, Brad Dusek, who had been the Redskins' regular left linebacker, was starting after recovering from a dislocated shoulder. Coleman moved to the right, and has grown progressively more confused every week.

"We need a lot from Monte and we felt this was the best way to go to help both him and the team, "Larry Peccatiello, the linebacker coach, said. "It means Brad has to adjust, too. But we think Brad's been around long enough to handle it."

Even though Joe Cribbs, Buffalo's best back, may not play because of cracked ribs, the Bills are expected to try to run against the Redskin linebackers. Buffalo has played best this season when it has had an effective ground game, enabling it to control the clock.

Roland Hooks, who replaces Cribbs, caught 13 passes for 111 yards last week as a substitute. In 1977, he ran for 155 yards against New England.

The Bills can be explosive, although they've been inconsistent this season. Quarterback Joe Ferguson, who has 22 touchdown passes and 18 interceptions, relies heavily on two quality receivers, Frank Lewis (59 catches) and Jerry Butler (46), a former Clemson star who is faster than anyone in the Redskin secondary.

"They are really a well-balanced team," Redskin Coach Joe Gibbs said. "Their defense is ranked No. 3 in the league, the same as their offense. From our standpoint, it will be interesting to see how we rebound from the loss to Dallas. When you win four games in a row, like we had, you have a tendency to relax. But we should have every reason to be aggressive in this one, if we want to go to the playoffs."