"It turned out to be a day-to-day injury, not severe, let's put it that way," coach Claude Noel said after practice.
Kane went down during practice the day before, after getting tangled with Anthony Peluso on the boards, and had to be helped off the ice favouring his right leg.
It looked like Peluso fell on the leg and it might have been Kane's knee that was injured.
Noel said the left winger's status for Friday's game was uncertain but he hadn't been ruled out.
"Potential yes, we'll have to wait and see."
If he doesn't play, he will be missed. Kane has been one of Winnipeg's more reliable forwards this season, with three goals, two assists and a team-leading 34 shots on goal.
His energy and more physical game has seen him move from the second to the top line.
He isn't the only injured player as the Jets play their eighth game Friday. Winnipeg's forward lines in particular have been taking a beating over the intense early schedule.
Centres Bryan Little and Jim Slater missed practices this week for what Noel termed "maintenance," although he says it looks like both would be ready Friday.
Right wing Chris Thorburn, however, has been placed on the injury list and the Jets have called up Patrice Cormier from the St. John's IceCaps in case he's needed.
Whether he sees any ice time likely depends on who else is fit enough to play.
Cormier played 10 games but not a lot of minutes with the Jets last season and was happy to get the call, although he didn't answer it.
He said he was in a movie theatre and when he left he noticed he had missed 14 calls.
"Excited but surprised," is how he described his reaction.
"I didn't really know what was going on. I watched the game against Montreal, I didn't see anyone — usually you see guys get hurt."
The Blues (4-1-0), meanwhile, are the kind of team the Jets (3-4-0) need to measure themselves against if they want to be competitive in the Western Conference, suggested centre Olli Jokinen.
"I think it's a good challenge, I think it's a good test for our team," he said.
"They probably feel that they're close to winning the Cup. Every year for the last two years they've been right there."
The Blues have never won the Stanley Cup. They missed the playoffs in 2010 and 2011 but with new coach Ken Hitchcock in charge they won the Central Division in 2012, losing the conference semi-final to Stanley Cup winner Los Angeles.
Last season they finished second in their division to eventual Stanley Cup winner Chicago but lost in the quarter-finals to the Kings again.
The Blues will be coming to Winnipeg after playing in Chicago Thursday night, but Jokinen didn't think that was going to make much of a difference.
"They don't take any teams lightly," he said. "They play the same way every night."
Noel, meanwhile, was Hitchcock's assistant with the Columbus Blue Jackets and replaced Hitchcock on an interim basis when he was fired.
St. Louis will be coming to Winnipeg without forward Maxim Lapierre, who is meeting with NHL officials over a hit Tuesday to San Jose's Dan Boyle that sent him off on a stretcher.
It's expected that Lapierre will be fined and receive a lengthy suspension for the hit that drove Boyle's head into the boards.
Note to readers: This is a corrected story. A previous version incorrectly listed Kane as having 30 shots on goal.