Vikings coach Leslie Frazier said he is hopeful Percy Harvin will be on the practice field Friday. The receiver, who leads the NFL in receptions with 62, missed his second consecutive practice Thursday, still dealing with a sprained left ankle suffered Sunday at Seattle.

Still, even with Harvin in serious pain and with a bye next week, there seems to be a push to get the receiver on the field against Detroit.

"If he can go, we'd play him and rest him after the game," Frazier said. "So we'll see how he does tomorrow."

After spraining the ankle in the third quarter Sunday, Harvin returned to the field but clearly was not his usual explosive self. Frazier said Thursday he's not quite sure what Harvin would need to show to get the green light for Sunday.

"It's hard to say," Frazier said. "Until we watch him move around. We'll see him tomorrow and then we'll make that determination. Is he well enough to go out and play without putting himself in harm's way?"

Harvin wasn't the only offensive star to miss Thursday's practice. Running back Adrian Peterson left the Vikings' facility earlier in the day because of a stomach illness and did not practice.

Apples and oranges Let the record reflect that Thursday marked the first time that a public comparison was made between Peterson, a perennial All-Pro and the NFL's rushing leader, and Riley Reiff, the Lions rookie offensive lineman.

But Vikings defensive coordinator Alan Williams insists Reiff's recent contributions to spark the Lions offense have been similarly important as the juice Peterson consistently gives the Vikings attack.

"[Reiff's] a little bit like Adrian Peterson in that you can't simulate him in practice. Everybody thinks with Adrian that, 'Hey these are just designed plays for him and if we stop this, [we're OK].' But when you get into a live situation, Adrian Peterson is a different deal. That's the same things with the extra lineman coming in. [Reiff] does a great job. He's athletic, he gets his pads down and he's going to be a handful."

Drafted with the 23rd overall pick in April, Reiff's settling into an unconventional role, getting an extended look as a sixth offensive lineman. Reiff, a tackle during his college days at Iowa, is playing a tight end type of role and providing extra power to the Lions' run blocking. Detroit had a season-high 149 rushing yards Sunday.

Hustle lacking The Vikings have forced only three turnovers in their past four games and none since Harrison Smith's interception return for a touchdown early in the third quarter against Arizona. But most troubling in Sunday's loss in Seattle, Williams said, was the occasional lack of hustle his unit showed.

"We want to make sure we continue running to the football," Williams said. "And there were some loafs in the ballgame. And those loafs are turning down hits or not running full speed or not getting up off the ground. We saw some of those, which are uncharacteristic of the defense."

Etc. • Sunday's game will be a "Salute to Service" military appreciation game. Players will wear decals on their helmets representing the military branches and will use camouflage gloves and towels. The Vikings have asked fans to arrive early to participate in a card stunt, which will reveal a patriotic message during the national anthem.

• A.J. Jefferson will remain the starter at cornerback with rookie Josh Robinson staying in the nickel role.