Those reports have now been strengthened by the news that the 47-year-old has ended his association with the Welsh national team.
"Regretfully, Chris Coleman has resigned from his position as Wales National Team Manager with immediate effect," read a statement from the FAW.
"Chris was appointed manager in January 2012 in very difficult circumstances and has guided Wales to the semi-finals of Euro 2016, an incredible achievement that inspired a nation."
Meanwhile, chief executive of the Football Association of Wales Jonathan Ford added: "We are extremely disappointed to see Chris's tenure as Wales manager come to an end.
"The FAW and Wales as a nation will be eternally grateful for the job he has done over the last six years as national team manager, from travelling the length and breadth of Wales outside of the media spotlight to talk to players and supporters, to guiding us to the semi-finals of the European Championships.
"We wish Chris the very best of luck for the future as he returns to club management, a desire for which he has always been honest and open about."
Sunderland are expected to confirm Coleman as their new head coach by Sunday.