Ajax coach Frank de Boer has said that Derk Boerrigter only has himself to blame for failing to carve out a career at the club.
The Dutch winger left Ajax in July to join Celtic on a four-year deal.
De Boer believes that the 27-year-old lacked the determination to succeed at the Amsterdam club.
"I gave Derk many opportunities at Ajax but it didn't work out. He wasn't comfortable at the club because Viktor Fischer was ahead of him and Lucas Andersen was behind him and coming through," De Boer told the Daily Record.
"We looked into the future and saw more in the young players at the club. He also didn't have the best of luck with injuries and he wasn't very self-critical.
"In situations like that you must look at yourself and if there is a player behind you who is coming through, then you need to raise your game. That aspect of his game could have been better."
Boerrigter has made nine appearances for Celtic.
