Mike Thomas missed another day of practice yesterday and Redskin Coach Jack Pardee said his status for action Sunday against the New York Giants was "very doubtful."

"His foot is still bothering him, still hurting him," Pardee said yesterday after a two-hour workout. "Whatever's wrong with him, well, those things aren't cripplers, but they hurt."

Redskin team physcian Stanford Lavine examined Thomas again yesterday and described the running back's injury as "a tiny little incomplete crack of the cuboid bone," and added that the injury is usually treated much the same way as a sprained ankle.

Could Thomas play Sunday? he was asked.

"Sure he could play if he feels no pain," Lavine said. "It's improving, and it's minimally sore. But that's his decision."

Thomas said his foot is still hurting as much as it ever has. He was asked if he thought he might be able to practice today and said, "I doubt it. I don't know if I can go Sunday. It just keeps hurting aching. I just have to wait and see."

Pardee said he would not hesitate to use Thomas against the Giants, even if he misses today's workout, the last major practice session of the week. "If his foot isn't hurting him," Pardee said, "we'd use him."

If Thomas still is ailing, Pardee said he will start John Riggins at fullback and Clarence Harmon at tailback, the same unit that opened against the Eagles last week. Newcomer Benny Malone and rookie Tony Green would also see some action at tailback, he said.

Malone, aquired in a trade with Miami last week, still is limping slightly on a sprained ankle, but has participated in every practice this week and should be available.

The Giants have announced they will start Joe Piscarcik at quarterback Sunday ahead of Jerry Golsteyn, although Pardee said yesterday both do most of the same things . . . cornerback Gerald Williams sat out the workout with a bruised thigh . . . The Giants are ranked 10th in the conference in total offense, seventh rushing and 10th passing.