It has been reported that Southampton have revived their interest in the French midfielder after selling fellow midfielder Pierre-Emile Hojbjerg to Tottenham Hotspur.
West Ham and Everton also want the 24-year-old, who is available for £20 million, according to the report, which has added that the former Manchester City man is interested in returning to the Premier League.
Ntcham joined Celtic from City in the summer of 2017 and has been a superb player for the Glasgow giants.
The former France Under-21 international has won the Scottish Premiership and the Scottish League Cup thrice each, and the Scottish Cup twice with the Hoops.
The 24-year-old has established himself as an important player in the team, and he is ready to return to the Premier League for ambitious clubs such as Everton, West Ham or Southampton.
However, Celtic may not be willing to sell Ntcham easily even if they are offered £20 million in transfer fees.
After all, the Glasgow giants are aiming to win their 10th successive Scottish Premiership title this season, and until and unless manager Lennon finds a suitable replacement, he is unlikely to sell the 24-year-old, especially as the season in Scotland has already started.