The junior, who will be listed second on the depth chart behind freshman C.J. Gable, said he missed Friday's workout because of food poisoning.
"I've been eating a lot," he said. "I wasn't eating at one place. I don't know where I got it from."
Washington went to the student health center and received shots and three bags of intravenous fluids.
It was the latest setback for a player who has been slowed by hamstring and knee injuries since training camp.
Washington participated in all drills Saturday and said he had regained his strength after the illness.
"I'll be ready to play," said Washington, who has rushed for 736 yards and nine touchdowns.
Said Coach Pete Carroll: "He's ready to play a lot."
Starting linebackers Brian Cushing (knee) and Dallas Sartz (hip) participated in all drills as the Trojans went through their final practice.
"I'm still taking it easy a little bit -- I'm not going to go crazy out there or anything," Cushing said. "On Monday, I'll let it all go."
Cushing said the Trojans were sharper in the last few days than at any time in their bowl preparation.
"It's like you're playing after a long spring practice," he said. "The game is here now. You can feel it."
Quarterback John David Booty agreed.
"It's crunch time now, it is only two days away," he said.
Carroll said the Trojans spent most of the workout in a review mode.
"The guys were into it and made a real effort to display a sense of urgency about the timing and the quickness and the movement and all of that," he said. "It worked out just right. We're ready."
Sartz said he held back some but reiterated that he would play against the Wolverines in the final game of his career. Clay Matthews will play in Sartz's spot if needed, Carroll said.
USC defensive end Lawrence Jackson on Michigan's running game, which features junior tailback Mike Hart: "Their running back is patient and he trusts the offensive line. They're a good team, but I'm not going to say they're Super Bowl champions or the best team in college football. They run some good things, but if we come to play we should be able to stop them."
To keep with their regular home-game routine, the Trojans will conduct a walk-through today and then check into a downtown hotel.