The British Boxing Board of Control (BBBofC) is hoping to resume professional boxing in Britain in July but with strict conditions and no spectators.
Tyson Fury urges British fans to fight coronavirus as a nation by staying indoors
"There's not going to be big-name fighters out there," Warren told the BBC of the first fights likely after the lockdown.
"There is no chance of Fury v Wilder behind closed doors."
Promoter Bob Arum said last month a delay could be even longer because of the importance of gate receipts.
"The fans in the last fight put in almost $17 million into the coffers in purchase of tickets... how do you replace that $17 million?," he said in a Top Rank Boxing interview. "I mean, you don't.
"A Fury-Wilder fight might have to wait a couple more months until we can go back to full spectators."
BBBofC proposals for July, which are still being discussed with promoters, include boxers in Britain having to wear face masks during ring walks and being banned from using a spit bucket in between rounds.
Former WBA lightweight champion Anthony Crolla told the BBC it would be impossible to follow such rules to the letter.
"A boxer can't spit in a bucket? What if that fighter has a mouthful of blood?," he asked.