Oldham have given new one-year deals to captain Gareth Owen and Cameron Leeming.
Hooker Owen, 27, has been with the Roughyeds since 2014. He has made 128 appearances for the club.
Centre Leeming, 24, featured in ten of the last 11 games for Oldham in 2019.
Oldham coach Diskin said: “It’s always good to retain the club captain and especially a local lad like Gaz who is burning with passion for Oldham.
“Everyone I’ve spoken to about Gaz speaks highly of him. He had an accomplished upbringing at Salford where they still think a lot about him, as do lots of other people within the game.
“He’s good out of dummy-half. He’s got a long, accurate pass and I’m looking forward to working with him and helping him to further develop his game.
“Cam is a good, strong three-quarter. He’s consistent and reliable and a player I’m looking forward to working with.”