The Republic of Ireland manager was full of compliments for the Aberdeen winger as Celtic, Cardiff City and now also Birmingham City fight for his signature.
“I wouldn’t really be surprised by Celtic’s interest because he gives you something," said the former Hoops boss.
“He wants to take players on, he wants to go for it and that’s encouraging.
“He has been a star man for Aberdeen for the whole season. His attitude is really top class and good luck to him.”