Bears right guard Lance Louis has been placed on injured reserve after getting a blind-sided hit on Sunday by Vikings DE Jared Allen. (US Presswire)

The Chicago Bears' offensive line which has struggled all season will have to get by without its most dependable blocker. 

Right guard Lance Louis has been placed on injured reserve due to a torn anterior cruciate ligament suffered Sunday on a blind-sided hit from Minnesota Vikings defensive end Jared Allen.

The hit caused outrage at Halas Hall Monday. It occurred on an interception return by Vikings CB Antoine Winfield, and came high, near Louis' head. It caught Louis with his feet planted firmly and the force of the hit caused his knee injury.

Coach Lovie Smith called it an unnecessary play on Allen's part and suggested it could lead to some problems from the league office for Allen.

"Jared Allen plays the game a certain way, a good player in our league," Smith said. "But I think there are some plays when you look at them again you say, ‘Hey, we could have done without that.’ I think our game could do without that play.

"We have an injured player right now based on it. I think you could have gotten a block a little bit differently. That’s about all I should probably say about it. I’m sure the league will look at it and they’ll give an opinion about what they think.”

After the game, Allen said he didn't think it was a dirty play.

"He’s running to make a tackle, so I just went to block him," Allen said. "I never intentionally try to hurt anybody. My condolences to him and his family."

Bears DE Israel Idonije said at one point it was the kind of block he might have thrown, but the game has changed due to rules designed for player protection.

"There have been a number of rules put in the game now that you can't hit a defenseless player," Idonije said. "Lance's vision is clearly downfield (on the play). Allen hits him on his blind side. At that point in the game he could have easily (gone) shoulder to shoulder, he could have laid him out with just using his hands to his chest, lot of options.

"Especially Lance is quick, he’s fast, but it’s not a situation where he was just blazing and he had to lay out to make a saving play. He hit him that way because he chose to hit him that way. Unfortunate because Lance has played very well for us."

Idonije agreed with the notion Allen could be looking at league action.

"That’s why you have officials and you have people that review the film afterward and hand out penalties for people that do the game a disservice because of malicious acts," he said.

The injury to Louis' left knee is particularly harmful to his career for another reason. He is in the final year of his first contract and is an unrestricted free agent after this season.

The Bears also lost left guard Chris Spencer to a knee injury. Edwin Williams replaced Spencer, and Williams started the second half of last season for the Bears. But they had to replace Louis with benched tackle Gabe Carimi, who had never played the position.

The only other true guard the Bears have is Chris Riley, an undrafted free agent practice squad player from Illinois State. Undrafted rookie James Brown is listed as a guard/tackle, but is really a tackle who has been taught some guard assignments.

They would have had one other, but Chilo Rachal quit the team last week after being benched and was placed on the reserve/non-football injury list.

Smith on Monday said it's premature to think they might leave Carimi at starting right guard.
"I just know what happened yesterday and Gabe Carimi played well at the right guard position for us yesterday," he said. "We were pleased with what he was able to do. It's a little bit different, even at the right tackle position.

"He's been playing out in space and it's a different animal inside like that. But Gabe is a tough guy and he said he would be ready to go with whatever we asked him to do and he showed that yesterday. All we can do is go on what he did yesterday and it was impressive what he was able to do at the guard position yesterday."

Follow Chicago Bears reporter Gene Chamberlain on Twitter@CBSBears.