Sinclair received treatment for a hamstring injury at parent club Charlton prior to the crucial home victory over Barnet last weekend but he was forced off just before the hour mark.
He has resumed full training and will be monitored ahead of the trip to the Pirelli Stadium.
Akpa Akpro was also a doubt to face Barnet with a thigh problem but he came through that game. However, he suffered some effects and was unable to train until Thursday.
In order to preserve their Football League status, Grimsby must win and hope Barnet fail to beat already-promoted Rochdale.