Washington safety Nate Williams suffered a concussion at Notre Dame and likely won't play Saturday against Arizona.

Already thin in the defensive backfield, the Huskies welcomed free safety Greg Walker, who returned to practice Thursday after tweaking his knee the day before.

The prognosis on Washington’s other safety, Nate Williams, isn’t as good.

Williams has undergone a battery of tests since suffering a concussion last Saturday at Notre Dame, however, he hasn’t been cleared by the medical staff and won’t play Saturday against Arizona.

“He just didn’t test out well,” coach Steve Sarkisian said.

Unlimited Digital Access. $1 for 4 weeks.

Williams’ streak of 18 consecutive starts will end, and he’ll likely be replaced by junior Victor Aiyewa, who would make his second start.

Sarkisian said freshman Nathan Fellner will also see time at strong safety.

Fast starts

Washington has scored in the first quarter in every game this season and has touchdowns in three opening drives. The Huskies attribute much of the success in the first quarter to Sarkisian, who calls plays and scripts the first 15 plays before the game.

“The majority of the time, it’s Thursday night,” Sarkisian said. “We talk as a staff on what everybody likes. We come up with a lot more than 15 plays.

“Ultimately, what we’ll do is take the 15 that we like to get us in a rhythm, to get the personnel groupings on the field, to hopefully get the quarterback in a rhythm, do the things that we do well but also to pose a threat to the defense. And then the other plays, we just want to make sure they get called throughout the game.”

Running back Chris Polk said the offense has “a sense of comfort because we know what’s coming.”

The Huskies have scored 35 points in the first quarter, but they’ve also allowed 40.

“As an offense, we can only control what we do and we can control the ball and put points on the board to help out our defense,” tight end Kavario Middleton said. “Who doesn’t want to score first? You get a head of steam. And good things tend to happen.”


• WR D’Andre Goodwin (concussion) did not practice but has been cleared to play Saturday. He’s expected to see time only in an emergency situation.

• RB Johri Fogerson has the flu and has not been with the team this week. It’s unknown whether he’ll play Saturday.

• Washington’s schedule to date ranks as the toughest in the nation among 238 Division I teams. UW’s opponents have a combined record of 21-4.

Percy Allen: 206-464-2278 or pallen@seattletimes.com