Grimsby player-boss Paul Groves has confirmed he is looking to bring Preston's Michael Keane and Portsmouth's Richard Hughes to Blundell Park on a permanent basis.
Both players spent the final weeks of last season on loan with the Mariners, and have impressed Groves despite being unable to stop the side's relegation to Division Two.
Groves told the Grimsby Telegraph: "There's going to be a fee involved with Michael Keane and that will put a strain on the deal.
"But it's something that we are in talks about and looking at what we can do. He is a good age, has proved he can do it in the First Division and is versatile too. He's definitely one we want to consider."