The 30-year-old Petta has not played for Celtic for more than a year and was on loan to Fulham last season.
The Rotterdam-born 30-year-old started his career at Feyenoord and joined Celtic on a free transfer from Ipswich in 1999.
The 30-year-old Petta has not played for Celtic for more than a year and was on loan to Fulham last season.
The Rotterdam-born 30-year-old started his career at Feyenoord and joined Celtic on a free transfer from Ipswich in 1999.
