Former Chelsea defender Slobodan Rajkovic is without a club.
Rajkovic spent the past three years with Italian club Palermo but was released after they finished bottom of Serie B last summer.
A 16-year-old Rajkovic signed for Chelsea in 2005.
The centre-back, tipped to succeed John Terry in defence, had spent the previous summer at Arsenal's youth camp.
Andre Villas-Boas gave the Serbian centre-back his first start for Chelsea, in a behind-closed-doors friendly against Wycombe Wanderers in 2011.
That same year Rajkovic was sold to Hamburg in a £1.8m deal.
His career never really ignited, making just 42 appearances for the German side in four years.