The 23-year-old Belgium international is struggling with a niggling toe injury.
“The likelihood is that he will need a procedure. If he has to have an operation Vincent will miss the start of the season,” City boss Mark Hughes told the club’s official website.
“We sent him to a consultant surgeon at the end of last season and he recommended injecting the toe and giving him six weeks complete rest, but he was suffering the same amount of pain again in training in Germany.
“He’s been back to see the surgeon now. We hoped the rest would cure it but it’s a bit more complex than that. It’s important that we address it now and make sure Vince is fit for the rest of the season.”