Looking for right mix on the offensive line

It may not matter who wins the UCLA quarterback job if the five guys standing in front of him can’t keep him in games.

The Bruins struggled last season with their protection of quarterback Josh Rosen, who was forced out of two games with concussions and missed the Cactus Bowl because of the lingering effects of those massive hits.

Only two starters have returned from that offensive line, making it one of the team’s biggest question marks. Returners Michael Alves and Andre James have been joined in the starting lineup during spring practices by right tackle Jake Burton, center Boss Tagaloa and left guard Josh Wariboko-Alali.

While Alves has remained at right guard, James has manned the featured left tackle spot after playing right tackle last season. Tagaloa and Burton are both converted defensive linemen, with Burton making his switch before last season and Tagaloa before the start of spring practices.

The rash of position switches has led to some predictably rough moments. Snaps have flown over quarterbacks’ heads, and the linemen repeatedly have been beaten by an aggressive pass rush.

“There have been some tough times out there,” Burton acknowledged Tuesday, “but we’re just grinding through it and that definitely builds that chemistry between us.”

The Bruins have used many quick-developing plays as part of coach Chip Kelly’s blur offense, though Kelly said they were not designed to help mask any weaknesses along the offensive line.

“You’ve got to be sound everywhere you are,” Kelly said, “so I don’t think there’s that concept of, if something happened quickly” it would help the offensive line. “I’ve never thought of it that way.”

The linemen would like to emulate last year’s group in at least one way: The same five players started every game, helping spark a resurgence in one of the nation’s top passing attacks.

But the Bruins gave up 29 sacks, ranking sixth in the Pac-12 Conference, and their running game averaged just 113.4 yards per game, ranking ahead of only pass-happy Washington State among conference teams.

Enter Kelly and new offensive line coach Justin Frye.

“He’s awesome,” Burton said of Frye. “If we’re slacking, he’ll definitely get on us, but he’s been teaching us a lot of new things.”

Burton said adjusting to the pace of Kelly’s offense requires getting the play call in quickly and making sure to be in adequate shape to run so many plays.

It also helps not to look back.

“We have a lot of new guys,” Burton said, “so I think the biggest thing is putting last season away and looking forward.”

He’s baaaack!

After a relatively low-key final college season, Rosen was back to slinging the bravado in an ESPN the Magazine interview released Tuesday.

Rosen, expected to be a top pick in the upcoming NFL draft, said he wanted to be the winningest quarterback in league history.

“I’d say six titles,” Rosen said, “but if Tom Brady gets six, I’ll say seven.”

Rosen also compared himself to radioactive material because of his provocative nature, saying, “I think if you can take radioactive material and concentrate it, you get something real special out of it.”

Rosen was featured on the cover while holding a finger over his lips alongside a caption reading, “Josh Rosen won’t shut up and throw.”

Etc.

Linebacker Brandon Burton wore a no-contact jersey after suffering an undisclosed injury in a practice. … Defensive backs Will Lockett and Quentin Lake each made excellent interceptions.