"Shane came away with Ireland at 16 and that was the first time I saw him," O'Dea said.
"He was raw and he's developed almost day by day. He's getting better and better and he'd be more than capable of doing a job at Celtic."
Long scored 24 goals in the English Championship this season but was unable to help the Royals into the top flight as they crashed 4-2 to Swansea City at Wembley in the playoff final yesterday. His name has been linked with various clubs including West Ham United (unlikely now they were relegated) and of course Celtic.