Panathinaikos have admitted they could find it difficult to reach an agreement with William Gallas.
The French defender is a free agent after his contract with Arsenal expired earlier this summer and there will be no shortage of suitors for such an experienced campaigner.
To bring in a player of Gallas' calibre without having to pay a transfer fee is an attractive prospect for many clubs, including Panathinaikos.
The Greek giants have contacted Gallas but are unsure whether they can meet his wage demands.
Panathinaikos vice-president Dimitris Gontikas concedes the club may have to identify other transfer targets.
"We made an offer to the player, but it is difficult to reach an agreement," Gontikas told the Daily Mail.
"We are continuing talks with his representatives and hope to find a solution, but it's not easy.
"Gallas interests us, but we'll look elsewhere if there are other possibilities."
Paris St Germain and Juventus are among the other clubs to have been linked with Gallas in recent weeks.