Holcomb could start for Vikings

Vikings quarterback Tarvaris Jackson missed his second straight day of practice Thursday, and it’s appearing more likely that veteran Kelly Holcomb will start for Minnesota against the Kansas City Chiefs.

Jackson injured his groin in the fourth quarter against Detroit last Sunday, and has been unable to participate in the first two practices of the week.

But Vikings Coach Brad Childress was still playing it coy Thursday, saying the window is still open for Jackson to recover and play at Arrowhead Stadium on Sunday.

“I’m still keeping it open because I watched him move around and he did better this morning,” Childress said.

Holcomb, acquired late in the exhibition season in a trade with Philadelphia to provide more experience behind Jackson, has been working to get acclimated with the Vikings and appears to have leapfrogged incumbent backup Brooks Bollinger on the depth chart.

Offensive coordinator Darrell Bevell said Holcomb was “absolutely” ready to play if the Vikings need him Sunday. He also said that missing practice is more detrimental to a young player such as Jackson, who has only four career starts, as opposed to a veteran.

“I’ll be honest with you, Tarvaris needs every rep that he can get,” Bevell said. “He needs to be in there. He needs to be running the offense.”

Still, the Vikings said that if Jackson is healthy, he’s the starter.

Kellen Clemens is ready to step aside and be the New York Jets’ backup quarterback again.

“It was a lot of fun and it was a great experience being the starter for a week,” Clemens said. “Hopefully that’s going to pay dividends down the line.”

Coach Eric Mangini said Chad Pennington will be the starter when his injured right ankle is fully healed. Based on how he has looked in practice this week, it appears he’ll be under center Sunday against Miami. And that’s OK with Clemens.

“As quarterbacks, we all want to compete and we all want to be out there playing on Sundays,” Clemens said. “I understand that Chad’s the starter. My role is the backup and I’ll make the most of the reps that I get and be as ready as possible if my number’s ever called. It’ll be turning back to what it was before if Chad’s able to play, and it’ll just be an adjustment that I’ll have to make.”

Linebacker Manny Lawson will miss the rest of the San Francisco 49ers’ season after tearing a ligament in his left knee.

Lawson, a starting outside linebacker in the 49ers’ 3-4 defensive scheme, went down with the injury Wednesday. The injury didn’t initially appear to be serious, and Lawson rode on a stationary bike for the rest of the team’s workout.

But tests determined Thursday that Lawson tore his anterior cruciate ligament.

“I was really looking forward to doing big things this year for my team,” said Lawson, who feared the worst after hearing a pop in his knee. “The hardest thing is just knowing I won’t be able to be out there practicing and playing in games with the guys.”

Lawson is second on the team with 14 tackles, showing impressive improvement from his rookie year. He started 11 games last season after San Francisco chose him with the 22nd overall selection, making 65 tackles and 2 1/2 sacks.

Dolphins middle linebacker Zach Thomas underwent tests for a possible concussion, and he may miss Sunday’s game against the New York Jets.

Thomas played every snap in Miami’s loss last week to Dallas but said he felt “a little lightheaded” in the locker room after the game, Coach Cam Cameron said. Thomas complained of a migraine Wednesday and missed practice, which led to the tests.

Thomas has fought migraine and concussion problems in the past but has missed only 13 games in a 12-year career. A decision on whether he can play this week is likely by today, Cameron said.

Indianapolis Colts tight end Dallas Clark, right tackle Ryan Diem and outside linebacker Rob Morris -- all starters -- missed their second straight practice, and Coach Tony Dungy has not said whether they will play Sunday at Houston.

Clark and Diem have neck injuries, and Morris has an abdominal strain. Morris missed last week’s game at Tennessee.

The NFL has received and destroyed all materials it requested from the New England Patriots concerning videotaping of opponents’ sidelines.

A league statement said the team was in compliance with a request for tapes and other documents.

“The Patriots have fully cooperated and complied with the requirements of the commissioner’s decision,” the statement said. “All tapes, documents and other records relating to this matter were turned over to the league office and destroyed, and the Patriots have certified in writing that no copies or other records exist.”