The centre-half limped out of Friday night's 1-1 draw at Swansea after just seven minutes with a hamstring strain and faces three weeks on the sidelines.
The injury will rule Robinson out of the matches against Barnsley, Portsmouth and Leicester.
However, there is some positive news for the Lions with midfielder Liam Trotter and striker Kevin Lisbie poised to return to training following their recent lay-offs.
Source: PA
Source: PA