LOS ANGELES -- Left tackle Torian White will miss the rest of No. 12 UCLA's season because of a badly injured right ankle.

Bruins tailback Jordon James also is doubtful for next week's home game with his own ankle injury, coach Jim Mora said Friday night.

Those two key injuries during a 34-27 victory Thursday at Utah dampened Mora's excitement over another gritty performance by UCLA (4-0, 1-0 Pac-12), which is off to its best start to a season since 2005. Mora relished the Bruins' performance under circumstances including significant injuries, chilly weather and a tenacious Utes effort.

"To me, they're character-builders," Mora said. "Everybody wants it to be easy and pretty all the time. I don't. I want us to build character along the way, because I think that will serve us over time. I want us to get in hard games and tough environments, and I think that will serve us along the line. It's nice to grow and get better."

But the Bruins must grow without White, a sophomore mainstay on the offensive line.

White was hurt in the second quarter in Salt Lake City when two players rolled into his legs from behind. Mora said White has a broken bone near his ankle and a slight ligament tear.

White will have surgery next week, but Mora hasn't decided how UCLA will replace him when California visits the Rose Bowl next weekend.

Sophomore Simon Goines shifted from right tackle to left tackle after White was hurt, and Caleb Benenoch took over at right tackle alongside fellow freshman Alex Redmond at guard. Utah attempted to exploit that inexperience in the second half with blitzes and stunts.

The 6-foot-5 White started all 14 games at left tackle as a freshman last season, playing a major role in the Bruins' improved offense led by coordinator Noel Mazzone and quarterback Brett Hundley.

But UCLA is fairly deep on the line, and Mora thinks the Bruins can plug the hole. Goines and Conor McDermott can play left tackle, and UCLA also could move standout left guard Xavier Su'a-Filo to the spot.

The Bruins got better news on James after X-rays were negative on their leading rusher, who has 463 yards and five TDs. James, who replaced school rushing leader Johnathan Franklin as UCLA's starter this fall, is wearing a walking boot.

"He's in a boot to take pressure off it," Mora said. "I'd say he's doubtful, but I wouldn't rule him out."

UCLA has several options to replace James if he can't return immediately. Paul Perkins has rushed for 192 yards in four games as a backup, and Damien Thigpen played briefly at Utah in his first game back from injury this season.

The Bruins have plenty of additional areas to address during their long week off. They also committed 13 penalties for 100 yards against Utah, although Mora focused on nine of those calls as areas in which the Bruins could improve.

UCLA was the most penalized team in the FBS last season, although several Pac-12 teams ranked disproportionately high on that list.

"I don't give us an out," Mora said. "Every call is an important call because it affects the game, but we're talking about some things we can do to improve in that area. It's a challenge for us right now, and it's something we've got to get corrected."

Mora chose to focus on the positive aspects of the win, including six interceptions. UCLA hadn't picked off six passes in a game since 1987 against Stanford -- and that's just one reason Mora laughed when the longtime NFL defensive coach got several texts from friends afterward congratulating him on an "ugly" victory.

"Ugly? We had six picks, baby," Mora said. "I'll take it."