Gunners boss Arsene Wenger has made snapping up a new centre-back one of his major priorities for the coming couple of weeks, after allowing club captain Thomas Vermaelen to join Barcelona.
The Frenchman wants cover at the back, and sees Manolas – who starred for Greece at the World Cup – as an ideal option.
Olympiakos are rumoured to be resigned to losing their star defender for around £6.5m, with financial pressures in Greek football high and the player himself said to be ready to test himself at a higher level.
Although Arsenal are confident of tying up a deal, Manolas himself is thought to have minor reservations.
The 23-year-old is believed to want guarantees of playing time, which Wenger cannot offer with Per Mertesacker and Laurent Koscielny his first choice duo and Callum Chamber having impressed in a central position.
Manolas has 13 international caps and has previously played for AEK Athens.