Boss Paul Groves confirmed that Mansaram is facing a long spell out of the team, with a torn groin the suspected injury.
"The way it looks at the moment, unless we're fortunate, he could be out for two or three months," Groves told the Grimsby Telegraph.
"I'm no medical expert but we think he has torn the ligament from the bone near his groin - and that's not something that will heal in two or three weeks. We just have to wait and see."