The Washington Redskins' selection of Darrell Green in the first round of Tuesday's college draft led to two developments yesterday: a prediction by Mike Nelms' attorney that his client will be traded, and veteran cornerback Joe Lavender's decision to retire.

In addition, the Redskins have decided to move Mark May back to tackle from guard, where he was an on-and-off starter last season. May will be given a chance to beat out veteran George Starke at right tackle, a position May played in college at Pittsburgh.

Richard Bennett, Nelms' agent, said the Redskins' decision to draft Green, a standout kick returner, "presents the real likelihood of a deal being made." Nelms is a three-time Pro Bowl kick returner who became a free agent at the end of last season.

"There is a significant disparity between what I think Mike is worth and what the Redskins think he is worth and I don't see how we'll ever have an agreement," said Bennett. "No matter what the team says, I think it would be hard for me to separate their first-round draft pick from Mike Nelms. The Redskins don't need two return men and they obviously are going to spend a significant amount of money to sign their No. 1 pick.

"It seems they will either make a trade for Mike, or they won't do it and we will work up a deal with the United States Football League."

But both General Manager Bobby Beathard and Coach Joe Gibbs say they have no intention of trading Nelms, who has been one of the team's most valuable players. Gibbs, especially, is vehement about not hurting the makeup of the team that won the Super Bowl.

"We certainly want to sign Mike," Beathard said. "The draft had no connection with Mike, and I don't expect it will affect our ability to sign him. I agree that we are far apart and I don't see how we can reach an agreement. We'll just have to work at it."

Nelms, who made $110,000 last season, reportedly wants at least $275,000 this year. The Redskins apparently are offering significantly less, probably $140,000 to $170,000.

The Redskins are convinced Nelms would rather sit out next season than play for what he considers insufficient salary. Yet there is a feeling at Redskin Park that Nelms may be on the downside of his career as a return man--and, they now have Green. Yet, before Nelms could be traded, he would have to work out a contract with the other team involved, which could be a stumbling block.

Mike Hickey, a scout with the New York Jets, yesterday called Green the best college return man he has ever seen. Asked about Nelms, Hickey said, "Mike Nelms? Death by draft."

Lavender, 34, is a 10-year veteran who has played seven seasons with the Redskins. He was beaten out as a starter last year by rookie Vernon Dean and wound up the team's nickel back.

With the drafting of Green, a standout college cornerback, Lavender was given little chance of gaining a roster spot next season. Although he had considered retirement before, he did not tell the team of his decision until after Green was drafted.

Green, whom the Redskins think is good enough to start immediately at cornerback, also is a trump card in their negotiations with Jeris White, the cornerback who sat out the 1981 training camp over a contract dispute. If White holds out for a long time again, he could find Green playing in his place.

However, the Redskins still do not have the depth at cornerback they want. Besides not making a trade to gain picks in the fourth and fifth rounds, Beathard admitted his other major disappointment in the draft "was not getting more help at cornerback."

The Redskins wanted to select three cornerbacks, but got just one. Beathard also sought James Britt of LSU, who went to Atlanta in round two, and Isaac Metcalf of Baylor, who went to Pittsburgh on round four. Beathard was convinced Metcalf was a "sleeper" who would last until the sixth or seventh round, where Washington would have a shot at him.

"I don't anticipate having problems signing any of the selections," Beathard said. "Before we took anyone, we talked to them about the USFL and they all said they were anxious to play for us."

Concerning the decision to return May to tackle, Joe Bugel, the line coach, said he was confident "Mark will push George very hard for a starting spot. It ought to be something to watch. George is getting on in years but he still can play."

In the Redskins' master plan, Bob Winckler, a 285-pound sixth round pick from Wisconsin, will beat out Fred Dean at right guard and May, at 285 pounds, will win the right tackle position. That would give Washington perhaps the biggest line in NFL history, with Joe Jacoby (295) and Russ Grimm (270) on the left side and Jeff Bostic (252) at center.

"Fred Dean is a legitimate backup player," Bugel said. "I just don't know if Fred can go 16 games weighing 255 without getting nicked (injured). When he doesn't have to play every minute, he is a better player. Winckler is like a Grimm, that kind of get-the-job-done attitude. He's had a weight problem, but he's under 300 now. He was all-Big Ten, so he's a player. He can start."

May was the starting left tackle for half his rookie season, then was moved to guard last season and wound up alternating with Dean. May played against 4-3 defenses and Dean against 3-4s. But both May and the Redskins consider right tackle to be his most natural position.

Lavender had 29 interceptions for the Redskins, fourth best in team history, and 33 for his NFL career. He made the Pro Bowl in 1979 and 1980 . . . Beathard and his scouts were busy yesterday signing players who weren't drafted. "Even with the USFL, there are a lot of good players out there," he said . . . Said Bugel, "The weight room was really smoking this morning with veterans. I guess they heard about the draft."