EDEN PRAIRIE, Minn. -- 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 preseason in a trade with Philadelphia to provide more experience behind the young 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.
In other injury news, safety Dwight Smith missed his second straight practice with a hamstring injury and fellow starting safety Darren Sharper (hip) was limited.
That makes the decision to keep veteran safeties Tank Williams and Mike Doss on the roster all the more important.
Defensive coordinator Leslie Frazier said he was preparing as if Doss and Williams would be playing most of the snaps in Sunday's game at Kansas City.
"We have to do that because neither Dwight nor Darren practiced yesterday, so you have to prepare that way," Frazier said. "Hopefully they will both be ready by Sunday, but we have to get Tank and Mike ready."
Doss has been bothered by a calf injury for the last month and hasn't played in a regular-season game since he tore knee ligaments while with the Indianapolis Colts against Washington on Oct. 22.
He has been practicing and said he feels ready to go if needed.
"It's been almost a year since I've been in a real, regular-season game," Doss said. "I'm looking forward to getting back out there."
Running back Chester Taylor (hip/oblique), fullback Tony Richardson (forearm) and receiver Troy Williamson (hamstring) were also limited in practice.
Copyright 2007 by The Associated Press. All Rights Reserved.
