Volz, a free agent after being released by Fulham last summer, recently attracted interest from German club Schalke, where he started his career.
The full-back, 26, joined Arsenal in 2000, but did not make a first-team appearance for the Gunners before signing for Fulham four years later.
He received a German international call-up in 2004, but did not play.
Volz, who played 146 times for Fulham, ended last season on loan at Ipswich Town.
Source: BBC Sport
Source: BBC Sport