Williams was limited in Wednesday and Thursday's practices, but both he and head coach Leslie Frazier were optimistic he would be able to play after experiencing no concerning soreness following those sessions.
"Everything based on what happened (Thursday) after practice he was feeling good, so he should be good to go," Frazier said.
The coach said he knew Williams wouldn't be at practice Friday. While that absence wasn't because of injury, the Vikings will monitor Williams' reps during Sunday's game.
"We'll have to monitor how he's doing in between series, just talk to him sometimes, see how he's coming along just to make sure that he's functioning properly," Frazier said. "But we'll kind of have to play it by ear."
Said defensive coordinator Alan Williams: "Just having the experience of a guy out there that has seen it before, and not only that but Kevin is still a good football player and his leadership. When the guys look at another guy like that in the huddle, it gives them confidence that we're going to get the job done. I can't measure it, Kevin being back."
Williams was one of seven Vikings listed on the injury report as probable, joining LB Larry Dean (shoulder), LB Erin Henderson (heel), RT Phil Loadholt (knee), S Mistral Raymond (shoulder), CB Josh Robinson (quadriceps) and C John Sullivan (knee). All except for Williams, who didn't practice, and Sullivan, who was limited, were full participants.
For the Bears, DE Julius Peppers (illness) and CB Charles Tillman (knee) are both probable. Peppers was limited in Friday's practice and Tillman was a full participant.
After giving up three sacks in their season opener and having RB Adrian Peterson stopped for 15 yards on his final 17 carries, offensive coordinator Bill Musgrave gave credit to the Detroit Lions' defensive line.
"I think the defensive front proved tough to block. We did miss some blocks. We had some negative runs, which is uncharacteristic," Musgrave said. "Usually when we run it with Adrian once, twice, three times in a row we end up in third-and-manageable or we have ourselves a first down. On Sunday in Detroit when we would run it, we ended up with minus yardage and that's uncharacteristic for us, so it's a combination of us not doing as well as we would expect and also Detroit playing very well."
QB Christian Ponder threw three interceptions, but Musgrave took some of the blame for that.
"He definitely was put in some tough positions and that's part of the art of quarterbacking, is knowing what to do when it's not there," said Musgrave, who played quarterback in the NFL from 1991-96. "Christian is a very prideful young man. He never gives up on anything. He's what you would term as a battler so when a play transpires in which it's not going to come off as designed, at times he has a tough time swallowing his pride and giving up on the play and ditching it and saying, ‘I'll come back the next play.' He wants to give it every last moment of availability. And that's what happened the other day instead of ditching it and moving on, trying to make something that really wasn't there."
Tim Yotter is the publisher of Viking Update. Follow Viking Update on Twitter and discuss this topic on our message boards. To become a subscriber to the Viking Update web site or magazine, click here.