Maccarinelli, 27, held the WBO belt for 18 months but lost his title when Londoner Haye added to his WBA and WBC crowns with a second round knock-out of their O2 Arena showdown.
Cunningham beat Pole Krzysztof Wlodarczyk in a rematch last May to clinch the IBF title but the fighter from Philadelphia wants to fight Haye for a cruiserweight unification clash.
Big Macc, though, is desperate for a return to the big time.
"Maybe we'll be able to do something with Cunningham," said Warren.
"But it is just a matter of time for Enzo now as he'll have to fight his way back into contention.
"My advice to him is to fight the ranked guys to move up the rankings.
"It all depends on what the future holds for David Haye as he holds three of the four cruiserweight belts.
"There is talk of him stepping up to heavyweights and if he vacates the title, it might make it easier for Enzo.
"Enzo must fight his way back into position of becoming a number one contender."