Derek Niven is set to be sidelined for up to six weeks after damaging ankle ligaments.
The Scotland-born midfielder, who is Chesterfield FC’s longest-serving player, picked up the injury during training this week.
Initially it was thought that he could have broken a bone but a hospital X-ray revealed ligament damage which could take between four and six weeks to mend.
Niven, 27, a busy box-to-box player, started his career with Raith Rovers and joined the Spireites from Bolton in 2003.
He has started more than 250 league games for Chesterfield and regained his place in the first-team after battling testicular cancer.
Niven, who scored the last-ever goal at Saltergate, has started four games this season and he may already be targeting the Colchester clash at the B2net on Saturday, October 1, for his comeback.