The reports come as Hoops boss Neil Lennon has admitted defeat in his pursuit of Romaine Sawyers.
Ivory Coast midfielder Kouassi has barely featured for the Scottish champions since signing for £3m two-and-a-half years ago.
Brought in by then manager Brendan Rodgers, the 21-year-old never managed to break into the first team at Parkhead.
Kouassi has made just 22 appearances for Celtic and hasn’t featured since being substituted with a cruciate injury in League Cup tie against Hearts last October.
Panathinaikos are looking for new recruits and sporting director Nikos Dabizas is in the UK as part of the hunt.
With Kouassi still in recovery though it is unclear whether he would would pass the medical stage of a transfer.
Meanwhile, Celtic’s hopes of landing Romaine Sawyers look to have gone.
They had an offer rejected for the attacking midfielder earlier this month as Lennon looks to bring in new faces.
However, West Brom are understood to have agreed a deal with Brentford for a fee close to £3m for Sawyers.
The 27-year-old looks set to move to the Hawthorns with Celtic now having to pursue other options.
Elsewhere, Celtic left-back Kieran Tierney might finally seal his move to Arsenal in the coming days after reports that the two teams have “reached a deal”.
ESPN Brazil claim the Gunners have come to an agreement with the Hoops for the Scotland international.
Unai Emery’s side had a series of bids knocked back from Celtic with Arsenal unable to reach their £25m valuation for Tierney.
Lennon has admitted that the 22-year-old’s head has been turned by the speculation.
“It’s difficult for him to keep focused at the minute because he’s only human,” Lennon said.
“We’re supporting him all we can.”