Chelsea are watching developments at cash-strapped Napoli, it has been revealed.
Italian football journalist Ciro Venerato claims staff and players at the Naples giants have not received any pay since July.
Earlier this year it is thought the Napoli boss took a wage reduction in order to help Napoli save the jobs of club staff.
Football.London says Napoli, who will play Roma on Sunday, could look to shift some players off their wage bill, should Venerato's claims prove true.
And it is thought Chelsea, who strengthened their backline with the summer signing of veteran Thiago Silva, could consider a swoop for Koulibaly - if Napoli are open to a cut-price sale.
Reports suggest Chelsea could also be in the market for an older winger as back up to their promising young attackers.
It is thought Mertens, 33, who has scored three goals and provided three assists in seven Serie A games this term, could fit the bill following Pedro's and Willian's departures.
