The Serbian has drawn attention with a number of composed performances in Serie A.
The 22-year-old has spent the last two seasons in the Italian top-flight, having made a move from Genk in the summer of 2015.
He has made 73 appearances for Lazio, netting 10 goals, and those exploits have now seen him attract big-money offers from afar.
Milinkovic-Savic’s representative, Mateja Kezman told calciomercato: “I’ve received huge bids, over €50m in the past few weeks.
“As we agreed at the start of Sergej’s contract though, he’s not for sale this summer. He’s very happy at Lazio and wants to help the team fight for a place in the Champions League next season.
“After that, you can never 100 per cent know what will happen in life…
“We’re in no rush, the lad is happy at Lazio, he’s growing and [coach Simone] Inzaghi is doing good things with him.
“He’s only 22 and next year we’re expecting to do great things with the Biancocelesti.”
Milinkovic-Savic recently saw his efforts praised by countryman Aleksandar Kolarov, with the experienced Manchester City defender telling Il Messaggero: “Milinkovic-Savic, he's an amazing player, he's Lazio's and the national team's future".