Defensive end Mat Mendenhall, who started every game last season but whose job seemed in jeopardy now, left training camp before tonight's practice. Team officials said they did not know why Mendenhall had left or where he had gone.

"I don't know what happened, maybe it was one of those personal things," Coach Joe Gibbs said.

I just found out he had left," General Manager Bobby Beathard said, watching practice. "I don't think he talked to anyone before he left."

Tight end Clint Didier, Mendenhall's training camp roommate, said, "All I know is that I came back into my room this evening and everything was cleared out but my stuff. No, Mat never told me anything about it. He is a quiet guy. He's also a nice guy."

Mendenhall, who lives in Utah, could not be reached for comment.

Mendenhall, 26, was selected in the second round of the 1980 draft from Brigham Young. He started at left end last season, making 34 tackles in the regular season and seven more in the postseason.

Redskins coaches had said they would likely keep seven or eight defensive linemen on the roster. Todd Liebenstein, a second-year player, seemed to have moved ahead of Mendenhall during training camp and Tuesday Richie Petitbon, coach of the defense, said the competition for the eighth defensive lineman position seemed to be between Mendenhall and Pat Ogrin.

In another development, the Redskins acquired third-year cornerback Anthony Washington from Pittsburgh for a 1984 draft pick. That puts them one above the 70-player limit, assuming Mendenhall returns.