The drug Orthovisc is designed to provide additional lubrication in the joint, but Wells suffered significant swelling after the injection and did only a minimal amount of work on Wednesday and Thursday.
He likely will be a game-time decision Sunday in Minneapolis.
Wells started his first NFL game last week and gained 50 yards on 16 carries. He was expected to start again before this recent setback.
Wells underwent surgery in September to repair a meniscus tear, and the injection was a normal part of his follow-up treatment.
Wells needs to practice more on Friday in order to play a significant role in Minneapolis. "You want to go out there and play full speed, not swelling up to where I can't bend my knee," he said.
If Wells can't start, then the Cardinals likely will revert to starting Tim Hightower. Hightower has been an effective runner this year when he has not fumbled. He has lost three fumbles, which led to his benching.
It has been clear coach Ken Whisenhunt has a quarterback dilemma: choosing between two bad alternatives.
In three starts, Hall completed just barely 50 percent his passes and had one touchdown and four interceptions.
Not that Anderson was better.
He's completed 53.5 percent of his passes and has four touchdowns and seven interceptions.
He has made many poor decisions, the most recent coming last week when he forced a pass to Larry Fitzgerald in the final minutes. It was intercepted, ruining the Cardinals' chance to tie or go ahead.
The Cardinals' schedule had a lot to do with Whisenhunt's decision to go to Anderson.
Whisenhunt didn't want to start Hall in Minneapolis at Mall of America Field. It's a loud venue, and Hall has struggled at home.
In two weeks, the Cardinals play in Kansas City.
So Whisenhunt chose to go with a veteran accustomed to playing in difficult places.
Anderson has better players around him than he did in his last starts. Last week was the first time he played with the starting three receivers since the second quarter of the first game.
Steve Breaston, a starter, returned last week after missing three games because of knee surgery. Early Doucet, the No. 3 receiver, returned the previous week.
SERIES HISTORY: 21st regular-season meeting. Series tied, 10-10. The clubs have split the last four meetings, but the Cardinals beat the Vikings, 30-17, in 2009. The offensive line did a nice job protecting Kurt Warner, who was not sacked. The Cardinals intercepted Brett Favre twice and held Adrian Peterson to 19 yards on 13 carries. The Cardinals gained 398 yards of offense.
BY THE NUMBERS: 31st — That's where the Cardinals rank in turnover ratio. They are minus-9, one better than the Panthers. Quarterbacks have been intercepted 23 times, tying with the Panthers for most in the NFL.
QUOTE TO NOTE: "We say that every week so that kind of saying is getting old. We keep losing these games and we keep coming back with the same results. We are who we are. We are a 3-4 team." — Outside linebacker Joey Porter, when asked if the team is underachieving.