Abbott admits he is not fully confident of holding onto the pair but believes he will receive the financial support needed to find quality replacements if necessary.
"It is important I get a squad ready for next season. If they (Raven and Graham) want to be a part of it, fantastic. If they don't, we will look elsewhere," he told the News & Star.
"I will stick to my gameplan in terms of what I think they are worth. They have to look at that and see if they can get better elsewhere. That is what players do.
Abbott feels there is unlikely to be any progress in contract negotiations until the club's League One status is secured.
"Once we get the points we need, they will come in and sit down with me again," he added.