The youngster has caught the eye of a number of clubs, including Everton, following to a string of impressive displays at the Britannia Stadium.
As Commons is out of contract at the end of the season, the First Division side are wary of receiving less than the player's valuation come next summer.
The 20-year-old has started around half of the club's league matches this term, while also coming off the bench in five, scoring one goal.
Gislason is worried by some of the advice given to the player by his agent, and believes Commons's decision to leave or not is out of their hands.
