EUGENE -- Oregon may have injuries added to insult.

Ducks quarterback Justin Herbert and wide receiver Dillon Mitchell are in concussion protocol following hits sustained during Saturday's 44-15 loss at Arizona and their status for this week's game against UCLA is undetermined.

Oregon coach Mario Cristobal was unsure when the injury occurred to Herbert, who was 24 of 48 for 186 yards with a two touchdowns and an interception against Arizona, but said it "might have been at the end" of the game.

"It looks like that might have been the point, but not being a doctor, I can never comment on exactly when," Cristobal said. "But anytime someone seems to have taken on a hit, we're always going to take the highest level standard in terms of assessing guys to make sure safety is at the forefront, the priority."

Herbert was sacked once and had six carries for 31 yards, including back-to-back carries with goal-to-go in the final 90 seconds of regulation, the latter of which featured him getting hit while trying to reach the edge of the end zone.

Many Ducks fans were perplexed as to why Herbert was still playing late in what was a four-possession game in the first place. Cristobal explained Oregon was trying to end the game "on some type of positive note offensively," though it failed to score on the last drive and turned it over on downs at the one-yard line.

"We wanted to be able to move the ball and to get out of there having at least some sort of confidence in moving and potentially scoring," Cristobal said.

Should Herbert, who is completing 59.6 percent of his passes for 2,069 yards with 20 touchdowns and six interceptions this season, be unable to play against UCLA on Saturday (4:30 p.m., FOX), the Ducks will have to turn to backup quarterbacks Tyler Shough and Braxton Burmeister.

Cristobal said who will start will be decided once doctors make a determination on Herbert, but that Shough and Burmeister could see more reps with the first-team offense during practice this week.

"Should the case be where it's something where they have to play right away, absolutely, those guys will be taking a bunch of reps," Cristobal said.

Mitchell left Saturday's loss following a brutal hit by Wildcats safety Tristan Cooper on a third-and-eight pass from Oregon's 37-yard line during the third quarter.

Mitchell, who had six catches for 69 yards and a touchdown in the loss, was down on the field for several minutes but got up under his own power, though he did not return.

Jaylon Redd, already among Oregon's starting receivers, took over as the lead wide out after Mitchell went down.

-- James Crepea | jcrepea@oregonian.com | @JamesCrepea