Myles Jack, UCLA's multi-talented linebacker, was lost for the season after suffering a knee injury in practice on Tuesday.
Jack, a junior, was injured near the end of practice during a non-contact drill. He tore a meniscus in the knee and underwent surgery Tuesday evening.
Coach Jim Mora was subdued and to the point on Wednesday, saying only, "Myles suffered a knee injury and had surgery last night and he's out for the year."
Asked about the injury, Mora, said, "It is a significant knee injury."
It was the latest bad news in what was building to a big season for the Bruins. They have lost three of their best defensive players for the season in three weeks.
Defensive tackle Eddie Vanderdoes suffered a knee injury in the opener against Virginia. Cornerback Fabien Moreau broke a bone in his foot against Brigham Young on Saturday.
Jack, who was considered one of the top linebackers in the nation, will be the hardest loss to absorb. Besides playing linebacker, he was an effective running back in goal-line and short yardage situations. The dual abilities earned him Pac-12 offensive and defensive freshman of the year honors in 2013.
"We have some people with skill levels who can do other things," defensive coordinator Tom Bradley said
The Bruins do have linebackers who are strong against the run and defensive backs that cover one-on-one in space. But Jack could do both well.
UCLA will now have to mix and match players, a difficult chore against up-tempo offenses that rarely huddle. The No. 9 Bruins get a significant test against No. 16 Arizona in Tucson on Saturday. The Wildcats use a no-huddle spread offense.