When Sugar Ray Leonard defends his world welterweight championship Monday night at 10 against lightly regarded Bruce Finch, it will be his first of perhaps four fights this year.

Although he admits that there are no blockbusters on the horizon, Leonard says he wants to stay active and give all "deserving challengers" a chance at his title.

"Now that I've gotten through the top contenders, I'm going to give the others a chance," Leonard said today at Harrah's. "I'll give any deserving challenger an opportunity for the title."

Sources close to Leonard say he probably will fight Roger Stafford of Philadelphia in May or June. Atlantic City has bid for the bout, but facilities could be a problem, in which case the fight is expected to be in the Meadowlands.

Leonard eliminated any hope of a match with middleweight Marvin Hagler, and also said he isn't considering rematches with Wilfred Benitez or Roberto Duran. That led to speculation that his big fight this year would be with Alexis Arguello, the WBA lightweight champion, sometime in the fall.

Arguello's record is 74-4 after he defended his title Saturday with his 60th knockout, stopping Bubba Busceme in the sixth round in Beaumont, Tex.

"Welterweight is my natural weight," Leonard said. "I ventured to 154 pounds to fight (Ayub) Kalule (a ninth-round technical knockout June 25 in Las Vegas). I went in at 156 and left the ring at 145.

"A Hagler fight won't materialize," he continued. "I can't carry 160 and he won't fight at 154. I always said that was the ultimate challenge, but it's not going to happen."

When asked about Benitez, whom he beat for the WBC welterweight title in November 1979, Leonard shook his head.

"There is no purpose to another Benitez fight," he said. "We challenged him before Hearns and he turned us down. Anyway, he's moving up to challenge Hagler.

"It's over for Duran," Leonard went on. "He realizes that. I don't think he'll ever fight again. Big fights like that only come along every four or five years. You can't just wait for those, so I'll stay active and give anyone who deserves it a shot at my title."

There has been some question regarding Finch's credentials, but the 27-year-old former club fighter from Milwaukee is 30-3-1 and has won his last 11 fights, eight by knockouts.

Since coming under the guidance of veteran trainer Al Davis in Las Vegas, Finch has knocked out Zeferino Gonzalez in eight rounds, won the North American Boxing Federation welterweight title by stopping Pepe Dominguez in the 10th round last April, then knocked him out in the second round of the rematch in June. In his last fight, Finch knocked out Sonny Perez in the third round July 29 in Las Vegas. He was scheduled to meet Milton McCrory when Leonard fought Thomas Hearns last September, but the fight was canceled when McCrory injured his hand.

"Al has been a big help to me," Finch said of his 67-year-old trainer. "He taught me to punch to the body and then switch my attack back to the head. He also helped me sharpen up on my basic skills."

Davis has been training fighters since 1943, but Finch is the first fighter he has handled who is fighting for a world title. He says all Finch was lacking was confidence when he came to him.

"I worked on his conditioning, but mostly I worked on his mind," Davis said. "He doesn't have any fear now. He goes into the ring with confidence."

Finch's last loss was a second-round knockout by Hearns Sept. 7, 1978, in Detroit. The others were knockouts by Peter Ranzany and Larry Bonds. Leonard has knocked out all of them.

"I trained on my own for the Hearns fight," Finch said. "I didn't have sparring partners or nothing. I wasn't in real good condition like I am now."

Finch won't make a prediction on Monday's fight and said his strategy is a secret. He describes himself as a "boxer, puncher--I can do it all."

The only odds on the fight have been given by Jimmy (the Greek) Snyder: Leonard at 20-1. The only betting in this gambling oasis is pick 'em whether it will last eight rounds or fewer. The fight will be shown on cable television on Home Box Office.

After asking Finch at a joint press conference, "When do you feel like going down?" Leonard's latest prediction was a knockout in the fourth round.

Derrik Holmes, a junior featherweight from Washington, will try to improve his 16-1-1 record against Franco Terragoza of Stockton, Calif. in one of the preliminaries.