The former Sydney FC favourite headed to South Korea in January after long eyeing an overseas move, and made 13 appearances for coach Kim Gi-dong’s third-placed finishers.
Having carved a regular K1 League starting spot mid-season, O’Neill, 26, fell out of favour at the back end of the campaign and it’s understood negotiations to bring him to seven-time Thai champions Buriram are at an advanced stage.
The iconic club - now coached for a second time by newly-appointed Brazilian Alexandre Gama - are in an unfamiliar eleventh spot 11 games into the season.
The elaborately nicknamed Thunder Castles were champions as recently as 2019 and, in 2016, with Gama in charge, became their nation’s 'Invincibles', cleaning up four domestic crowns in a calendar year - the Kor Royal Cup, Thai Premier League, FA Cup and League Cup.
O’Neill, who has a single Socceroos cap, spent four seasons at Sydney FC, having arrived from Perth Glory in 2015.
He won two A-League titles and picked up an FFA Cup winner’s medal during his stellar stint with the Sky Blues.
