The National Football Post first reported the story.
Jones injured his ankle as he jumped out of bounds during Thursday night's game against the Cleveland Browns at Soldier Field. He left the game, and while X-rays on the ankle were negative, an MRI done Friday morning revealed a torn ligament, according to the Post.
"Everyone was hoping last night that it wasn't anything too serious," said Bears tight end Greg Olsen Friday on "The Afternoon Saloon." "It's unfortunate, [it's] last preseason game -- he's had a great preseason and offseason for us. He's worked hard to be in top shape like he was before the knee injury. It's part of the game, it's an unfortunate side that everyone kind of takes for granted, but it's just kind of the way it goes. Hopefully, he makes a speedy recovery and we can get him back as fast as we can."
The Post reports that Jones' injury will require surgery and an 8-10-month rehabilitation process.
Jones' injury does open the door for backup running back Adrian Peterson. Olsen said the team has complete confidence in Peterson to get the job done.
"You know what you're going to get with AP," Olsen said. "He's tough as nails, he's going to give you everything he's got, he's been around the league for a while and he's done a great job. He's great on special teams; he's great when he comes in. You can count on him to get the hard yards and run hard and he's tough. You can't say enough good things about the kind of guy he is and what he brings, and the whole team has a lot of confidence in AP."