United signed the midfielder last year and immediately loaned him out to Belgian sister club Beerschot where he has impressed.
Coulibaly scored five goals in his first season in the Jupiler Pro League but missed the final stages of the campaign throgh injury.
Sky Sports are reporting that Galatasaray have made a £12.9 bid for the Malian which is understood to have fallen short of United’s valuation.
AC Milan were also reported to have shown interest in the player last season.
With new manager Slavisa Jokanovic coming in this week, though not officially starting for another month, it’s not yet known what United are going to do with the player for next season. Coulibaly is due to remain in Belgium but they can call him back if they wish to do so.