William Saliba is resisting a new contract offer from Arsenal.
The Frenchman, who impressed out on loan in Ligue 1 with Marseille, is reportedly not wanting to extend his contract in north London despite returning to pre-season with Mikel Arteta's side.
It is claimed that Marseille, where Saliba excelled last term, are monitoring the defender's future.
Saliba has two years left on his current deal.
As such the Gunners are seeking a replacement, with Chelsea youngster Levi Colwill on the radar.
The Daily Mail have reported that should Chelsea look to sell the 19-year-old centre-back this summer, the Gunners are one of five Premier League clubs interested in potentially signing the former Huddersfield Town loanee, with Leicester City, Crystal Palace, Southampton and Everton also keen.