Manchester United are one of a number of Premier League sides keen on the promising Red Bull Salzburg attacker.
The Austrian club do not want to lose his services in the ongoing transfer window, but could be forced to reconsider their position if Sesko pushes to go.
The striker’s agent has held talks with Manchester United and asked the Red Devils about Ronaldo, who wants to leave the club.
He was told by Manchester United that Ronaldo is not for sale.
Ronaldo is keen to depart Old Trafford for a club involved in the Champions League and has been linked with several sides.
He has been named on the bench for Manchester United’s Premier League opener against Brighton on Sunday.
Sesko may believe that his chances of regular game time could be limited at Manchester United if he moves to the club with Ronaldo still on the books.
