The club have sent the 26-year-old for an MRI scan but a fault with the machine meant the scan was delayed.
"It's a problem that's been getting worse over time and it's got to the point where he can't carry on. He's getting quite a bit of discomfort," Manager Paul Groves told the Grimsby Telegraph.
"We're sending him for an MRI scan to see the extent of the damage. Would you believe the machine was broken earlier in the week? But we're hopeful of getting it done today or tomorrow."
The loss of Campbell will hit the midfield hard, the former Leicester man has played all across midfield this season. The departure of Marcel Cas will test the depth of the midfield although Groves has thrown himself back into the equation after a good performance against Plymouth.