Vickery has not damaged the anterior cruciate ligaments but his season - and possibly this summer's England tour to New Zealand - remains in doubt after his right leg was twisted awkwardly in a ruck.
Vickery was strapped up and tried to continue but, after two scrums, he limped off. He emerged from the changing room midway through the second-half on crutches and his knee packed with ice.
Wasps director of rugby Ian McGeechan said: "It is not his ACL. He got his leg twisted but, until he gets it scanned, nobody knows what damage he has done."
It was the only sour point in a crucial victory for Wasps which, coupled with Leicester's defeat at Bath, moves them into the Premiership's top four for the first time this season.
Wasps are past masters at timing their title challenge to perfection, having won a hat-trick of Premiership finals without finishing top of the table.
This year, they have had to come from further behind than ever before after winning just one of their first six games.
Tom Voyce and Paul Sackey scored the tries and Danny Cipriani kicked 19 points as Wasps completed their seventh consecutive victory.
McGeechan said: "The players have worked really hard and we are really proud of them. That last defensive play, when Sale went back 30 yards with the ball, showed the attitude.
"You don't get much spirit like that to the pound.
"The three games we played in the Six Nations without eight players set the atmosphere.
"I don't think people have noticed it but since we got all our players back from the World Cup, we have been consistent right through. We have only lost one Premiership game since October.
"Tonight was a tremendous game of Premiership rugby. It was nip and tuck, it was physical and you don't get many more competitive games than that.
"I thought our scrummaging was excellent. We had a 100% lineout and in critical games like this, that makes the difference."