The 34-year-olds both left the club in 2020 to try their hand at a higher level - Peter as a centre with Billingham and Rollo as a prop with Huddersfield.
Their invaluable experience at Level 4 will now be put to use "back home" as the club looks to build on the success, for both the Firsts and the Stags, achieved by retiring coaches Jamie Connolly, Ian Wilson and Antony Cameron.
They'll be joined by Andrew Turner as strength and conditioning coach and who will take a more involved coaching with the Stags.
In announcing the new coaching set up to the players Chris Webb said: "I feel the history and respect we all have for the club is vitally important as well as the relationships we have with you, the players and club members.
"Also, the knowledge and experience of the game we bring and the way the three of us see the game of rugby, how we like it to be played, plus the passion and drive to always be better can only make the whole squad improve.
"We also have the same views on the culture, environment, attitudes and expectations that are key to successful and enjoyable teams! "