Harris had been let go by the Chiefs on Tuesday and Minnesota brought him in a day later for a physical. The two sides agreed on a one-year contract. Harris spent the 2005 and 2006 seasons with the Vikings -- he was acquired from Oakland in the Randy Moss trade -- and was the team's starting middle linebacker in his final season with the team.

He had 96 tackles, 2.5 sacks, nine quarterback pressures and three interceptions in 14 games that year.

Harris departed as a free agent after the Vikings gave E.J. Henderson a five-year contract and moved him to middle linebacker. With Henderson lost for the season because of dislocated toes and his backup, David Herron, battling a hip injury, Harris could be the Vikings' solution in the middle for the rest of the season.

It remains uncertain if he will be ready to play Sunday in Chicago. Harris did not play in a game for the Chiefs this season and had fallen out of favor.

Tapeh, who played college football at the University of Minnesota, signed a five-year, $6 million deal that included $1.25 million with the Vikings during free agency. But he did not tell the team he had undergone a procedure on his knee shortly before signing the contract.

Tapeh had not been active since Week 2, and it became clear the sides were headed for a divorce this week when coach Brad Childress volunteered the information about Tapeh having hidden his knee issue.

It's unclear if the Vikings will attempt to recoup some of the bonus money they gave Tapeh, but that would not be surprising.

PLAYER NOTES

--LB Erin Henderson returned to practice Thursday after being limited the day before because of a knee injury suffered in the Vikings' victory over Detroit last Sunday.

--LB David Herron was held out of practice for a second consecutive day Thursday because of a hip injury suffered last Sunday against the Lions.

--WR Bernard Berrian was limited Wednesday and Thursday because of a knee problem. He suffered the injury two weeks ago in practice but has had back-to-back 100-yard receiving games and almost certainly will play Sunday in Chicago.

--TE Jim Kleinsasser was limited in practice Wednesday and Thursday because of a foot injury that has bothered him for three weeks. Kleinsasser, though, has been able to continue playing.

--WR Sidney Rice did not play Sunday, missing a game for the third time in four weeks because of a sprained posterior cruciate ligament in his right knee. He was limited in practice Wednesday and Thursday.

--CB Benny Sapp was limited in practice Wednesday and Thursday because of a hamstring injury. He was able to play last Sunday against the Lions.

--S Madieu Williams, who hasn't played this season because of a neck injury suffered early in training camp, isn't ready to return but has been cleared and is expected to be back after the Vikings' bye week. That will come up following Sunday's game in Chicago. Williams continues to do limited work in practice.

GAME PLAN: The Vikings prefer to run the ball but this is one game where they must consider using the passing game early and often. The Bears are 12th in the NFL in total defense but are giving up 236.3 passing yards per game to rank 27th in the NFL. Chicago is fifth against the run, surrendering only 74.3 yards on the ground.

Minnesota quarterback Gus Frerotte has had a few big strikes in recent weeks but the desired consistency from the aerial attack has to be established. This would be as good a time as any to work on that aspect, especially when you consider the Bears' secondary has all sorts of issues.

Cornerbacks Charles Tillman (shoulder) and Nathan Vasher (wrist) are among those battling injuries. This could certainly be good news for wide receiver Bernard Berrian as he makes his return to Chicago after leaving during the offseason to sign a big free-agent deal with the Vikings.

Defensively, the Vikings will be facing a team that is 12th in the NFL in passing and 13th in rushing. By all accounts, Bears quarterback Kyle Orton is much improved and should be able to test the Vikings secondary.

The Vikings run defense remains one of the best in the NFL, but as always the concern is how the pass defense will hold up. The fact that the Vikings have some uncertainty at middle linebacker could be a factor.

David Herron, who has taken over for the injured E.J. Henderson, had to leave last Sunday's game against the Lions because of various ailments. There is a chance that Dontarrious Thomas could start in the middle only six days after signing with the Vikings. The Bears are certain to try to attack this area.

MATCHUPS TO WATCH: Vikings RT Ryan Cook vs. Bears LDE Adewale Ogunleye - Cook had a nightmare game last Sunday against the Lions' Jared DeVries. Now he faces Ogunleye, who only has 1.5 sacks this season but had nine sacks last season. He will present Cook with quite a challenge as he tries to rebound. Look for the Vikings to try to get Cook some help, possibly from a running back or tight end Jim Kleinsasser. Kleinsasser is considered a top-notch blocker and could prove to be vital in helping Cook get back his confidence.

Vikings WR Bernard Berrian vs. Bears secondary: Berrian already is excited to return to Chicago, and the fact the Bears' secondary is all banged up probably makes him that much more eager for Sunday to arrive. Starting LC Charles Tillman (shoulder), starting RC Nathan Vasher (wrist) and backup RC Trumaine McBride (shoulder) are all functioning at less than 100 percent. Vasher hasn't played in the past two games. Corey Graham and Marcus Hamilton will be the Bears only corners who are 100 percent. Berrian very well could put up a third-consecutive 100-yard receiving effort.

Vikings P Chris Kluwe vs. Bears PR Devin Hester: Kluwe got in hot water two weeks ago for punting the ball to Saints return man Reggie Bush and not putting it out of bounds as he had been instructed. Bush, who already had a punt return for a touchdown when he received his orders, had another significant return and then took another ball back for a score. Coach Brad Childress was furious with Kluwe after the game. Kluwe made it clear he expects to be told to punt out of bounds rather than put the ball in Hester's hands on Sunday. Hester has returned punts for touchdowns against the Vikings in Chicago the past two seasons, and even though he hasn't been nearly as effective on punt returns this season, Minnesota might not want to take any chances. The problem is that if Kluwe is told to get the ball out of bounds there is a chance a few punts could wind up being short and give Chicago excellent field position.

INJURY IMPACT: If David Herron can't start at middle linebacker, Dontarrious Thomas could end up in that role after signing on Monday. Thomas has previous experience in this defense - he played for the Vikings from 2004 to 2007 - and is familiar with the system run by coordinator Leslie Frazier. The Vikings continue to wait for wide receiver Sidney Rice to return from a sprained PCL suffered in Week 2. Rice would present a nice complement to Bernard Berrian as a deep threat and also would give Bobby Wade more of an opportunity to work out of the slot position, a spot where he is more suited to play.