Three days before the Super Bowl, the San Francisco 49ers are hurting.

Three starters -- wide receiver Dwight Clark, tight end Russ Francis and defensive end Dwaine Board did not practice today. When asked which of the three injured players gives him the most concern, 49ers Coach Bill Walsh said, "I don't know. We really won't know until they go all-out in the game."

Clark and Francis have hamstring injuries and skipped today's interview session so they could be treated at the 49ers' Redwood City training facility. Board has an injured shoulder. All three players dressed for practice. Clark spent part of the hour-long workout on the sideline playing catch with an assistant coach.

Wide receiver Renaldo Nehemiah (hamstring), guard Guy McIntyre (leg) and running back/return man Carl Monroe (hamstring) worked out on a limited basis.

The Miami Dolphins' receivers, slowed in practice this week by a soggy practice field that looks like "a divot-filled golf course," might have to alter their practice schedule to get in more work the day before the Super Bowl, the receivers coach said.

David Shula, the Dolphins' receivers and pass offense coach, said today the team might have to turn the normal pregame stretching Saturday at Stanford Stadium into passing drills to make up for lost time during the week at Oakland-Alameda County Coliseum.

"We might spend more time running some routes on the field," said Shula, who is the oldest son of the head coach, Don Shula. "We haven't been able to do as much as we'd like to do here."

The Oakland Coliseum turf, notoriously sodden since the days the Raiders played here, has been causing quite a few problems for the Dolphins' top-ranked passing personnel this week.

"We've really had to slow down," Don Shula said. "The field comes up in huge globs . . . we have not been able to work on our timing. You just can't go full speed on it.

"And to think I once accused (Raiders' owner) Al Davis of watering down the field."

Several of his players are worried about getting hurt, especially when they make their cuts during pass routes.

"There's always a possibility of hurting an ankle or a knee," said reserve wide receiver Jimmy Cefalo.

"It's a great possibility," said defensive tackle Mike Charles. "It's a real bad field. We could step in one of those holes (created by the lack of turf) and twist an ankle or get a bad sprain. It's a sod kind of field, with dirt, sand and then the grass on top. It just picks up really easily."

This is no laughing matter. Or is it?

"I'm pretty excited about it," said safety Glenn Blackwood. "After the last practice, I'm going to tear it up, pack it up, send it back to Miami, and resod my backyard."

The Dolphins said the problem is affecting their practices, but will not alter their performance against San Francisco in Super Bowl XIX at Stanford Stadium.

"I'm sure it is throwing the timing off in practice," said wide receiver Mark Clayton, "but we've worked together all year, so it shouldn't be a problem in the game."

The other "Marks Brother," Mark Duper, added: "We're basically working on the mental part, not the physical part."

Cefalo's helmet made a divot 1 1/2 yards long when he hit the ground this week.

"It's no slapstick joke. I just fell.

"But," he added, "six months of training isn't thrown off in three days."

Still, others say, there is little value in spinning wheels the week before the Super Bowl.

"It sort of tones you down in practice," veteran wide receiver Nat Moore said. "Right now, we'd like to be going full speed. Everybody's sort of treading on thin ice."

"There's people out there falling down all the time," said Vince Hef-lin, a backup wide receiver who plays on special teams. "The field looks like a divot-filled golf course. You can't cut the way you want to. The ground gives under your feet and the whole thing comes up and you have to stop and replace it.

"It's a great field for defensive backs."

Even punter Reggie Roby is having troubles. His left foot sank five inches into the ground before he put on special cleats.

Yet the Dolphins have not complained to the NFL and do not plan to move, Don Shula said. He went out of his way to praise the entire facility the Dolphins are using (locker room, weight room, the works). It's the field no one likes.

"It's the worst field I've ever seen," Clayton said.

The NFL selects the practice sites for the teams, but, in the San Francisco area, that's no easy task.

"Most of the fields over here are wet, because of the soil and the climate," said tight end Joe Rose, who went to college at Cal-Berkeley.

Coach Bill Walsh said the 49ers had to move from their Redwood City facility to Stanford Stadium one day last week because of the condition of their field. Otherwise, they have had no problems.

The Dolphins think their tribulations this week might help them on Super Sunday.

Moore said the Dolphins wouldn't mind rain. "It would work to our advantage after these practices," he said.

But sunshine is predicted. CBS commentator John Madden told Don Shula that the Stanford Stadium field is in "great condition," Shula said.

"It's a fast track," Shula said. "That's what I'm looking for."

In this scenario, the Dolphins are hoping it would be just like runners practicing with weights around their ankles before a race.

"I get the feeling that after running on that turf, we'll feel lightning quick," Cefalo said.