Jared Allen to battle former Viking practice squad player Sunday

One battle to keep your eyes on Sunday is Vikings defensive end Jared Allen vs. Tampa Bay left tackle Donald Penn.

Penn has Vikings roots. He was signed as an undrafted free agent in 2006 and began that season on the team's practice squad before being signed by the Buccaneers that October. Penn didn't appear in a game that season, but he started 12 of 16 in 2007 and has started every game for Tampa Bay since. Penn and Allen faced each other once, in November 2008. Penn held Allen without a sack in a 19-13 Buccaneers victory.

Allen, who has a half-sack from the Vikings' season opener, has looked at a lot of film on Penn. His impression?

"He's gotten better over the years, I'll give him that," Allen said. "He's a big guy [6-5, 305]. He likes to absorb pressure. I think the biggest thing, we have to go out and stop the run and create one-on-ones. If we can get into some one-on-one situations we can be successful."

Allen battled shoulder and knee injuries that season but didn't miss a game. He was on a conference call with the Tampa Bay media this week, and he remembered that 2008 game.

"I was fresh off a busted-up shoulder," he told them. "And I felt it. I'll never forget that game."

Penn is coming off his first Pro Bowl but still could be vulnerable. According to profootballfocus.com, he gave up six sacks, nine knockdowns and 36 pressures last season.

"I've always been a confident player walking onto a football field, because I've been doing this for such a long time," said Guion, in his fourth NFL season. "But you do learn something about yourself when your [role increases]."

Not jumping One thing Guion and Fred Evans -- who backs up at nose tackle -- will be concentrating on is not jumping offsides. Guion was whistled twice for offsides and Evans once for encroachment on San Diego's final drive of last week's game, when the Vikings were trying to get the ball back to mount a game-tying drive. Two of the three calls resulted in first downs for the Chargers.

"It's a mistake," Evans said. "Things happen. We owned up to 'em, we did it. And we promised ourselves we're not going to let it happen again."

Injury update Vikings coach Leslie Frazier said cornerback Asher Allen (toe) practiced well this week and should be up for Sunday's game, and he and receiver Michael Jenkins (groin) were listed as probable on the team's injury report. Both took full part in Friday's practice. Defensive lineman Adrian Awasom and linebacker E.J. Henderson (knee) were listed as questionable. Awasom took limited part in practice while Henderson sat out.

For Tampa Bay, receiver Sammie Stroughter (foot) and cornerback Myron Lewis (ankle) are out. Tackle James Lee (knee) is questionable, and defensive end Da'Quan Bowers (shoulder) is probable.