Midfielder Milinkovic-Savic reportedly has a verbal agreement to join Premier League giant United, with Ander Herrera having left for Paris Saint-Germain and Paul Pogba's future uncertain at Old Trafford.
According to reports, United is ready to offer €90million to prise Milinkovic-Savic from Lazio – which signed the 24 year-old Serbia midfielder in 2015.
"As I said a long time ago, it doesn't matter how hard it could be [to keep Milinkovic-Savic]," Lotito said. "We will see what the market can offer and all the conditions that are going to be.
"We [as a club] feel great with Milinkovic, as he feels with the club. Offers, if there will be any, will be considered in a spirit of cooperation in order to guarantee both the interests of the club and the player."
Milinkovic-Savic scored seven goals in all competitions last season as Lazio won the Coppa Italia and finished eighth in Serie A.