Washington Redskins defensive end Dexter Manley was informed yesterday by the National Football League that his application for reinstatement will not be considered before a full year has elapsed since he was banned permanently by the league.

Manley was suspended last Nov. 18 for failing a drug test for a third time.

His attorney, Bob Woolf, said in a telephone interview yesterday from his Boston office that he had received a letter from NFL Commissioner Paul Tagliabue stating that the league was not prepared to make an "exception" for Manley and review his application until one full calendar year had passed.

Woolf, who said he was disappointed with the league's decision, said he and Manley might explore the possibility of Manley playing in the Canadian Football League until he is eligible to return to the NFL.

"Dexter is in good health and working very hard," Woolf said. "He's in excellent shape and will be ready to play when he returns.

"What we have to consider is whether playing in Canada might be an option, so he can be better prepared for his return to the NFL."

Woolf said money was a factor in looking at Canada, since Manley will earn no income from the Redskins while under suspension. But an NFL source said Manley still is under contract to the Redskins, even though he is suspended, and could not play football for another professional team.

CFL officials were not available to comment last night.

Manley was banned permanently from the NFL on Nov. 18 for violating the league's substance-abuse policy a third time. He admitted he had used cocaine and was an alcoholic.

Manley's salary from the Redskins was about $500,000 a year, as were his off-the-field earnings. His contract with the Redskins would have expired after the 1989 season, but, with the suspension, the Redskins still retain his rights.

He was in his ninth season with the Redskins and until struggling some last year was considered one of the best defensive ends in the NFL.

Manley, 31, was in Houston and not available to comment yesterday. According to Woolf, Manley is working with Houston Rockets basketball player John Lucas's drug treatment center as a volunteer. "He's doing fine," Woolf said of Manley. "He's helping others."

The Redskins have taken a wait-and-see posture regarding Manley's future with the club. "It's in the hands of the commissioner until Dexter is eligible to return to the NFL," General Manager Charley Casserly said last night. "When that situation changes, we'll cross that bridge when we come to it."