The pair played the final few months of the season at Carrow Road on loan from Crystal Palace and Wolves respectively and Gunn appreciates that neither player is likely to fancy trips to Exeter, Brentford and Wycombe next season.
He said: "Signing them both was my hope at the end of last season had we stayed in the Championship.
"But we didn't and it will be tougher for that reason. Financially we need to be realistic. These guys have got contracts at a Premier League and a Championship club. They are both under contract for the next two years.
"Being in League One is going to make it more difficult to attract them than it was before.
"We are investigating it. I have spoken to Mick McCarthy and Neil Warnock but there is nothing more to add."