BALTIMORE, SEPT. 1 -- Suspended infielder Alan Wiggins must agree to undergo rehabilitation or evaluation for drug addiction or risk losing all of the remaining $942,441 on his contract, sources said today.

Wiggins remained at his home in the Baltimore suburb of Cockeysville today, serving the second day of an indefinite suspension issued Monday by Commissioner Peter Ueberroth.

Ueberroth did not explain the reason for the suspension, but sources said it was because Wiggins tested positive on one, and perhaps two, drug tests within the last two weeks. Wiggins also had drug problems in 1983 and 1985.

Wiggins and his agent, Tony Attanasio of San Diego, continued to refuse comment on the matter, and there were no indications Wiggins had decided to undergo a rehabilitation program for the third time in his career.

If he does not, he may not get the remaining $142,441 on this year's contract or any of his guaranteed $800,000 salary in 1988, sources said. Even if he does undergo a rehabilitation program, he'll forfeit $314,147.

That clause was written into his contract when the Orioles acquired him midway through the 1985 season. Under the agreement, Wiggins would automatically forfeit one-third of the balance of his contract if he tested positive for drugs again.

The Orioles would then be responsible for 90 percent of the remaining money ($565,499), and the San Diego Padres, his former team, would be responsible for 10 percent ($62,800). But if Wiggins refuses to undergo treatment, the Orioles may not have to pay him anything, according to two sources familiar with such matters.

"If the Orioles can show that drugs were hindering his ability to perform, they have a winnable grievance," an agent said.

Ueberroth's unwritten policy is that multiple drug offenders must undergo a rehabilitation program of between 60 and 90 days, then spend another 60 days in the minor leagues while undergoing regular testing.