John McEnroe, on sabbatical since January, said yesterday that he will play tennis again Aug. 19 in the Norstar Bank Hamlet Challenge Cup in Jericho, N.Y. The 16-man, $150,000 tournament will run through Aug. 24.

"It's become a very fine event," McEnroe said. "For me, it will be ideal: near home, very strong competition, and conditions just like the U.S. Open which begins right after."

Heading the field will be defending champion Ivan Lendl.

COLLEGES

Mount St. Mary's College of Emmitsburg, Md., will change its NCAA status to Division I by the 1988-89 school year.

"The main thrust of our move is to again be able to compete with the type of schools that we competed with in days gone by," said Jim Phelan, the school's athletic director and basketball coach. "The schools in our area that we have extremely good relationships with have all gone Division I.

"I'm talking about schools like American, George Washington, George Mason, Georgetown, St. Joseph's, Towson State and Loyola. We used to play all of these schools on a somewhat regular basis, but we can't really play them now because they're Division I and we're Division II" . . .

The College World Series game in Omaha was suspended because of rain with Oklahoma State leading Loyola Marymount, 7-4. Bryn Kosco singled home a run to start such a big fourth inning that it never got completed. The Cowboys had scored seven runs that inning and were still batting when rain stopped play a second time. The game is to be completed today, followed by Miami vs. Louisiana State, which was washed out last night . . .

Francis Peay will coach Northwestern's football team this fall, at least. He had been defensive coordinator, then became interim coach in March . . .

The NCAA will review Tennessee's in-house report on alleged improprieties in the athletic department before deciding whether to conduct its own investigation.

BASKETBALL

The Portland Trail Blazers wanted to get Jack Sikma, 31, from the Seattle SuperSonics but didn't like the price.

"When they started talking about two or three players and our No. 1 pick, I said, 'No, we like Jack Sikma very much, but we cannot decimate our team for Jack Sikma,' " Buck Buckwalter, the Trail Blazers' director of personnel, said.

FOOTBALL

Former Baltimore Colts coach Ted Marchibroda is the leading candidate to coach the U.S. Football League's Baltimore Stars, according to a source close to the team.

Marchibroda, most recently an assistant with the Philadelphia Eagles, also was an assistant with the Washington Redskins . . .

A group of agents, worried about the slow pace of negotiations with rookies chosen in this spring's NFL draft, wants to sit down with management representatives to talk about it.

"We are on the eve of what shapes up as the largest absence of first-rounders from training camp or the largest spate of last-minute signings that the league's ever seen," says Leigh Steinberg, who represents two first-round choices this year.

Steinberg said he has spoken to other agents and would like to set up a meeting involving an NFL representative -- perhaps Jack Donlan, executive director of the Management Council -- to explore reasons for what he sees as an unprecedented delay.

The agents claim only eight of 333 players chosen in the April 29 draft have been signed. Kenneth Davis, a running back from TCU, is the highest choice signed. The Green Bay Packers took him in the second round. The agents claim only four of the 27 first-rounders have even gotten offers from the teams that drafted them -- Tony Casillas by Atlanta, Brian Jozwiak by Kansas City, John L. Williams by Seattle and Joe Kelly by Cincinnati . . .

The NFL is still checking allegations that running back Irving Fryar of the New England Patriots gambled on sports, despite a polygraph test that supported his denial.

GOLF

Jack Nicklaus Jr. advanced in his quest for the only major title to elude his father when he survived the opening day of match play at the Amateur Championship in Lytham St. Annes, England. He made the round of 32 with a 5 and 4 victory over Laurent Lassalle.

HORSE RACING

Shahrastani held off 2-1 favorite Dancing Brave by half a head in a dramatic late sprint to win England's $511,000 Epsom Derby. Shahrastani, owned by the Aga Khan, went off at 11-2. Third in a photo finish was 12-1 Mashkour, ridden by American Steve Cauthen.

JURISPRUDENCE

Former race car driver John Paul Sr., 47, changed his mind and pleaded guilty in St. Augustine, Fla., to a state charge of attempted first-degree murder.

He had rejected a plea-bargain two weeks ago. The deal is that he won't be sentenced to more than 20 years in prison and that the term will run concurrently with any federal sentences. The state could have given him life if he had been convicted of wounding Stephen Carson five times in April 1983 in Crescent Beach.

BOXING

In East Rutherford, N.J., Bernardo Pinango battered Gaby Canizales with his left and won the WBA bantamweight championship on a unamimous 15-round decision. Canizales, making his first defense, had said Pinango was a one-handed fighter. He was right, but it didn't help him. Only about 1,500 turned out at 20,000-seat Byrne Arena.