The Washington Diplomats strengthened their injury-depleted defense yesterday by purchasing center back Nick Mijatovic, who shared 1979 NASL laurels as defensive player of the year, from the Rochester Lancers for an undisclosed amount of cash.

The 6-foot, 180-pound Mijatovic is one of the aggressive defensive stoppers Dip Coach Gordon Bradley has been seeking since injuries sidelined defenders Don Droege, Mike Dillon and Jim Steele earlier this year. The Yugoslavainnative played every minute of the Lancer's 29 games last season.

Mijatovic, 32, could be in the starting lineup Sunday in the Diplomats' home opener at RFK Stadium against the Philadelphia Fury. Rochester hasn't played a game yet, and Bradley does not know Mijatovic's condition. But fit or not, the Yugoslavian is a welcome addition.

"He is the defensive player I need," Bradley said. "I went after three defenders when the injuries hit me -- John Craven (Vancouver), Steve Pecher (Dallas) and Mijatovic. I got the one I wanted.

"Nick is strong and a commanding type of player," Bradley said. "He is very good. I knew he wanted to come here so I went after him. He wants to play with (Johan) Cruyff."

Mijatovic, who has given Washington fits playing for the Lancers, is expected to join the club this morning in time for practice.

"That's the type of person he is," Bradley said. "I told him I would meet with him following the morning practice and he said he would be here to work out."

Mijatovic began his pro career with Sloboda of the Yugoslavia First Division. He was an instant sucess with Rochester, and was chosen the club's most valuable player in 1976 and '79. Well-respected throughout the NASL, Mijatovic is a skilled defender and committed only 36 fouls in more than 2,700 minutes last year.

In Rochester, a Lancer spokesman said, "We need the cash. We feel he's in the twilight of his career, but he's still a very marketable player."

If Mijatovic works his way into the starting lineup Sunday, Bradley will use either Carmine Marcantonio or Gary Darrell to man the other spot in the middle. Incumbents Tommy O'Hara and Bobby Iarusci are the other starters.

Both Marcantonio, who scored Washington's goal in its 2-1 loss in Tulsa last week, and Darrell are converted midfielders who have filled in on defense.

While Bradley has apparently rid himself of one headache, another is beginning to develop. The touted offense Washington fans expected to see with Alan Green, Ken Mokgojoa, Lozano, Bobby Stokes and Cruyff has been less than overwhelming.

"I'll be very concerned if we don't score any goals Sunday," said Bradley.

"And it doesn't matter who is out there. If we don't show some offense, I'd think we have a problem."

Washington's offense was sharp in the first half against Tampa Bay but went flat in the second half and the Dips lost the opener, 3-2, in a shootout. There was little offense in the Tulsa loss.

Part of the problem has been the slow adjustment to Cruyff and Lozano. Both are explosive, leader types who need the ball to operate.

"At times, I've been confused out there," said winger Mokgojoa. "One person tells me one thing, another person tells me something else. I can't play my own game. It takes time to learn to play with a Cruyff -- he's so good -- and right now, I'm having problems."

Mokgojoa wasn't the only Washigton player who looked lost against Tulsa. Washington managed only 10 shots as compared to 21 against Tampa Bay.

Green, the Dips' leading scorer who made both goals against Tampa, didn't play in Tulsa because of a badly sprained ankle. The striker said yesterday his ankle was better and there is a good chance he'll play Sunday.

"We're using a lot of game situations this week to stress offense," Bradley said. "We want the players to attack, not hold the ball. We want to say to the defenders, 'Look out, I'm coming.'"

"The biggest problem is that we haven't come together yet on the field," said Cruyff, who has a sore foot, but will start Sunday. "There are a few adjustment problems but nothing that can't be worked out. You can't just take the ball down field and score a goal. It takes teamwork."