Sesko has reportedly verbally agreed on a contract to join Manchester United.
However, Red Bull Salzburg want £55 million for him, while United are willing to pay a lower fee than the price tag. They are prepared to offer £25 million plus half of the fee paid in instalments and then play and club performance add-ons.
Sesko himself had positive phone calls with Erik ten Hag this week, during which he reached a verbal agreement on personal terms.
The Slovenian striker is under contract at Salzburg until 2026 and has started the season in red-hot form, scoring two goals and providing an assist in three games in all competitions.
He enjoyed a fine breakout season at Salzburg last year, scoring ten goals and providing seven assists in 36 games in all competitions, despite only 14 of those coming as starts.