Ishmael Adams

UCLA cornerback Ishamel Adams is confident about what the Bruins' secondary can achieve this season despite losing four starters. (Genaro Molina / Los Angeles Times / August 9, 2013)

Navy SEALS took UCLA's football team a couple of hundred yards offshore recently and dropped them in the water.

If there was ever a moment for Bruins' defensive backs to ponder "sink or swim," this was it.

UCLA has to replace four starters in the secondary this season. Keeping one's head above water would seem to be the first order of business. Yet the Bruins are talking about making a much bigger splash this season.

"We have guys who have the mentality to be the best secondary in the nation," safety Anthony Jefferson said.

Cornerback Ishmael Adams echoed that idea.

"We have the opportunity to show we are the best secondary in the nation," Adams said.

It's quite a bit of swagger for a group of players who were in supporting roles a year ago with the Bruins, or in high school or injured. Considering what they will face, a little attitude may be necessary.

Playing in the Pac-12 with an untested secondary has a reality-TV-show feel. The coaches in the conference seem to form a fear-of-the-run support group from top (Washington State's Mike Leach) to bottom (Arizona's Rich Rodriguez) geographically. And that was before Sonny Dykes brought his squirrel derby offense to California this season.

So that "What, me worry?" look on UCLA defensive back coach Demetrice Martin's face has to be more than bravado.

"This is a very athletic group," Martin said. "They are very young, and they are going to do things young guys do. I'm letting them know there is no such thing as the wrong coverage as long we're in the same coverage every play."

Martin then mentioned again that the Bruins were "young" and he treats them that way.

"I'm giving them that rope," Martin said.

The hope is they won't trip over it.

The Bruins' secondary does have an entry-level position look once you glance at their resumes.

Jefferson is a junior but spent the first half of his UCLA career dealing with injuries — first a broken foot, then back surgery. Safety Randall Goforth played in 14 games as a reserve last season but is a sophomore.

At the corners, Adams, a sophomore, had his season abruptly ended after three games in 2012 because of shoulder surgery. Fabian Moreau, a redshirt freshman, came to UCLA as a running back and then was flipped to defense during training camp last year.

They won't get a break-in period.

"It's the Pac-12. We're expecting anything to come our way," Goforth said.

Others in the defensive mix include senior cornerback Brandon Sermons, and three freshmen — safety Jayon Brown, safety Tahaan Goodman and cornerback Priest Willis.

"I can't have that freshman syndrome," Willis said. "In high school, you can make a mistake and get away with it because of ability. You can't make those mistakes in college. Everyone has ability."

It's a daily learning curve. Brown was a linebacker at Long Beach Poly High. Willis comes with enormous potential but has been left chasing receiver Shaquelle Evans on a few occasions during camp.