The former Netherlands national team manager has said United will want to keep the Spanish goalkeeper at the club this season.
“He’s our best player for the past two or three years so we cannot let him go so easily.
“We want to sell at the same level as we pay. We want to keep him of course.”
Galatasaray want to keep hold of Muslera but could be forced into considering such a substantial offer.
Muslera played a key role in the Lions winning the league for a record 20th time last season and earning the right to wear a fourth star – Galatasaray also won the double for a record sixth time.
The experienced keeper has won three league titles at the Lions and also the Copa America with Uruguay.