LOS ANGELES (AP) — Quarterback Kedon Slovis is in the concussion protocol for No. 21 Southern California, increasing the likelihood of Matt Fink making his first career start at No. 17 Washington this weekend.

Coach Clay Helton confirmed Tuesday night that Slovis isn't currently cleared to practice or play.

Slovis was injured on the second play of the Trojans' victory over then-No. 10 Utah last Friday. Fink stepped in and passed for 351 yards with ample help from his outstanding receivers in USC's 30-23 win.

Fink is likely to lead the underdog Trojans against the defending Pac-12 champion Huskies (3-1, 0-1). Offensive coordinator Graham Harrell is working overtime to train his third starting quarterback in five games — and the non-quarterbacks who would be Fink's backup, including a walk-on safety and a starting receiver.

"We plan on playing Fink," Harrell said. "And if something happens, you're in a scramble situation and you've got to make the best of what you've got."

The Trojans (3-1, 2-0 Pac-12) installed a completely new Air Raid offense this season under Harrell, but have still managed a solid start despite upheaval at the scheme's most important position.

J.T. Daniels was lost to a season-ending knee injury right before halftime in USC's season opener, and 18-year-old freshman Slovis stepped in to start the next three games. He was outstanding in a victory over a ranked Stanford team, but threw three interceptions in an embarrassing overtime loss at BYU.

Fink realizes he could be playing for the permanent starting job if he performs well in Slovis' absence, but it's all tied to the Trojans' overall success.

"Every day is a great opportunity, especially today," Fink said. "Again, it (stinks) to see anyone on the team get hurt, but that leaves more opportunity and more doors for myself, so I'm going to go ahead and take that and run with it."

Fink will be USC's only scholarship quarterback at Washington if Slovis doesn't suit up. Jack Sears, who finished fourth in the four-man quarterback competition in training camp despite previous starting experience at USC, entered the transfer portal and hasn't returned to the team.

Fink nearly left the Trojans himself after spring football, entering the transfer portal and even taking a visit to Illinois. The Rancho Cucamonga native strongly considered a move to the Illini before returning to USC in June, citing a desire to stay close to home.

When asked to choose the best part of his performance against Utah, he cited the chance to celebrate afterward with his family. Fink's father was at practice Tuesday to watch him running the first-team offense.

"It's kind of surreal, (but) it's an amazing opportunity for me and the team to keep moving forward," Fink said.

Fink threw 18 passes in his first two seasons at USC as a backup to Sam Darnold and Daniels. He threw 30 more against the Utes, including one TD pass apiece to Tyler Vaughns, Michael Pittman Jr. and Amon-Ra St. Brown, his triumvirate of elite receivers.

Helton and Harrell are getting creative to prepare backups for the potential disaster of Fink going down with an injury.

Brandon Perdue, a walk-on junior who played quarterback sparingly in high school and junior college before moving to safety at USC, would be Fink's primary backup. He has been the quarterback of USC's scout team in practice, but hasn't thrown a competitive pass since some brief action for New Mexico Military Institute in 2017.

Harrell even put Vaughns behind center during practice Tuesday night, simply because he wants to have options.

"Tyler is a great athlete, and he can throw a football," Harrell said. "So we're giving him snaps. You've got to be creative in this situation."

Starting safety Talanoa Hufanga is in the concussion protocol as well, Helton said. The Trojans' leading tackler made a career-high 14 tackles against Utah in a breakout performance, but he also has a sprained shoulder.