Bullets guard Don Collins was unable to practice yesterday and may not be able to start in Boston tonight in what could be Washington's last game of the season.

Collins, who injured his right ankle in Sunday's overtime loss to the Celtics, limped around in his street clothes during the 2 1/2-hour workout at Bowie State and said he would try to play tonight, "but it's real painful. I don't know what I'll be able to do."

The Celtics hold a 3-1 lead in the best-of-seven NBA Eastern Conference semifinals. Game 5 will be televised on WDCA-TV-20 and broadcast on WTOP-1500 at 7:30 p.m.

Another injured guard, Kevin Grevey, still badly hobbled with a pulled abdominal muscle, ran with the first unit in practice yesterday. Shue said he expects Collins to be able to play tonight, but said if he can't he will have to go with Grevey.

"I feel all right," said Grevey. "I still can't run all out, but as long as it stays a half-court game, I can play. We're down to one last game, so we all have to play with our ailments. A lot of people have them. I just don't know how long I can play. I really hope Don can play because if he can't, it'll really put a kink in things and that's something we don't need right now."

Neither Grevey nor Collins have been effective the last two games. After scoring 14 and 17 points, respectively, in the first two games in Boston, Collins was scoreless Saturday and had only six points Sunday. Grevey has made only seven of 23 shots in the four games.

"We have a real problem in the back court," Coach Gene Shue said. "Don plays a running game, but there are no fast breaks in this series, so that reduces his effectivness. We need an outside shooter, but Kevin has been hurt."

Shue said he will stay with Frank Johnson as the other guard over John Lucas. "Frank is streaky," the coach said. "I don't know what he's going to do, but we have to go with him."

Johnson's three-point shot in the last seconds of Game 2 in Boston delivered the only Washington victory against the Celtics. In the two games since then, however, he missed 24 of 28 shots.

Only four teams in the history of the NBA playoffs have come back from 3-1 deficits to win a seven- game series. The Bullets are one of those teams, having come back against the San Antonio Spurs in the 1979 Conference finals.

"We aren't going to approach this game any differently that we have any of the others," said Shue. "In this series we have reduced the Celtics to looking like us. We forced them to play that way and it's taken away a lot of their weapons, especially the fast break. There aren't many more adjustments we can make. The bottom line is we're already doing the best we can."

The Bullets certainly weren't acting like a team on its way to the guillotine yesterday. There was plenty of laughing and joking and fun times mixed in with the long workout.

"They should be loose," said Shue. "They've played as hard as they can. They've been remarkable. It just seems we could be overmatched, but this season should really build our confidence and give us a big head start next year, no matter what happens the rest of this series.

"We're in no way giving up. I always feel there's a chance. If we go up there and take them Wednesday, then we come back home and who knows?"