According to Italian newspaper, Secolo XIX the Hoops (Celtic) have proposed a deal that will see a £1.8m loan fee paid for an initial season for the 27-year-old Gambian.
The Scottish club would then have an obligation to complete the transfer with a further payment of £5.8m.
Negotiations are likely to continue as the Serie A club want up to £9.8m for the tough-tackling Gambia international.
The 6ft 3in defender is likely to command a greater fee than that reported one in Italy, having joined the Serie A side for £7.1million from Genk in 2018.
The Lamin-born player was cautioned ten times in the Italian league last campaign in his 31 appearances.
Celtics also face competition from Premier League sides for his signature, with West Ham also reported to be interested.
The towering Gambian defender is available but he will cost the champions a huge transfer fee.