Panathinaikos have made tentative enquiries with departing Hearts captain Danny Wilson's representatives.
The Greens, who are third in the Greek Super League, have already had the 23-year-old watched this season.
And they will again be represented on Saturday, when the Scottish Championship title winners host Rangers in their final game of the season.
Wilson has been with Hearts since January 2013, having initially joined on loan from Liverpool before making the move permanent that summer.
He had joined the English Premier League club in 2010 after coming through the youth ranks with Rangers and into the Ibrox first-team as a teenager.
Wilson, who was also loaned out to Blackpool and Bristol City by the Reds, is also interesting Celtic.
The Scottish Premiership leaders' manager, Ronny Deila, admitted earlier this month that Wilson was a player he was considering.