The talent of Utah's young defensive linemen might get tested sooner rather than later.

The Utes announced Thursday that Koa Misi, Utah's most experienced defensive lineman, is "out until further notice with a back injury."

Misi hurt his back in Wednesday afternoon's practice when he was working in a light contact drill against offensive lineman Zane Beadles.

Utah coach Kyle Whittingham hoped it was just a back spasm and he'd return to practice soon.

Details of the injury weren't released from the school, which cited the federal regulation called the Health Insurance Portability and Accountability Act as the reason for keeping the information private.

Misi has been bothered by tightness in his lower back in past seasons, Whittingham said Wednesday after the injury occurred.

Nevertheless, he has been one of Utah's steadiest contributors the last two seasons, starting the last 11 games of the 2007 season and every game in the 2008 season.

He ranked third overall with 68 total tackles in 2008.

This year he entered camp about 10 pounds lighter and was a preseason All-MWC pick, as well as being on the watch list for the 2009 Ted Hendricks Award, which goes to the top defensive end.

If Misi is out for an extended amount of time, Whittingham said left end Derrick Shelby and backups Nai Fotu and Christian Cox must step up in his absence.

Fotu is the likely candidate to replace Misi at right end since he was listed as a co-starter along with Shelby at left end. He played as a linebacker last season but was moved back to end, his natural position, for the 2009 season.

"He is much more at home playing the defensive end spot," Whittingham said. "That is really where he is going to flourish."

Whittingham also said the Utes would consider moving sophomore starting tackle Lei Talamaivao or his backup, redshirt freshman Dave Kruger, outside.

The Utes could make such a move because they are deep along the line, even if they are inexperienced.

Kruger and freshman Latu Heimuli have had strong camps as has sophomore Sealver Siliga, the backup at nose tackle.

The Utes were in a similar situation last season when two defensive linemen, Zeke Tuinei-Wily and Isley Filiaga quit before the season started and another, Keni Kaufusi, never made it onto campus after his scholarship was revoked for his involvement in an altercation.

Then Kenape Eliapo, the current senior starting nose tackle, missed seven games with a broken foot and Talamaivao went down with a broken leg, missing the final 11 games.

The defensive line was still one of the Utes' strengths as the Utes finished the season ranked 11th nationally in total defense and 11th nationally against the run, giving up just 99.2 yards a game.

lwodraska@sltrib.com