Grimsby are interested in signing former Nottingham Forest defender Joe Heath, who is training with Exeter as he looks to earn a contract.
The 21-year-old, who spent the first half of the season on loan at League Two rivals Lincoln, is a free agent after leaving the Reds during the last transfer window.
Heath played for Town in a reserve-team friendly this month before accepting the offer to train with Exeter, and Mariners manager Neil Woods is keeping an eye on the left-back.
"We had a look at Joe recently and he did OK, and he is one we will keep an eye on," said Woods.
"It was always more of a case of looking at him ahead of the summer anyway."
Meanwhile, forward Adrian Forbes will continue his comeback from a broken leg with another outing for the reserves against Leeds on Tuesday night.