Rangers fans cannot expect Steven Gerrard to close the gap with Celtic next season should he become Ibrox manager, says Mark Warburton.
Warburton was Rangers boss for two years, leaving in February 2017.
Celtic thumped Rangers 5-0 on Sunday to secure a seventh successive title.
"If they expect Stevie G to come in and go and smash Celtic next season, win the league and get into Europe straight away then he is under inappropriate pressure," he said.
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Rangers are confident of appointing the former Liverpool and England captain following talks with the 37-year-old.
He is being lined up to succeed Graeme Murty, whose side were thrashed 5-0 on Sunday as their city rivals secured a seventh consecutive Scottish title.
"Success is being the number one club in Scotland and yesterday highlighted there is a significant gap between the two clubs," Warburton told BBC 5 live.
"Bringing the big name in, that buys Stevie some time, but that quickly evaporates.
"It will simply come down to him getting the backing of the board he undoubtedly needs.
"It's not a case of saying Stevie G needs £100m or £150m. He needs time, backing and a clear structure."
Warburton urged Rangers' board to make clear to their supporters that Gerrard was not expected to be an overnight success.
"The fan base is outstanding," he said. "They are also expectant and I think you want the board to come out and give the fans a realistic timetable of when they are going to close the gap and go ahead of Celtic.
"Every time Celtic go in the Champions League, X amount of million pounds lands in the Celtic coffers - that is the fact of it.
"To close that gap when Celtic are doing so well makes it so difficult for any club to close that gap."
Warburton said that who has the final say on transfers and the quality of the recruitment network are factors that "tend to get ignored in the excitement and euphoria of a manager being appointed".
However, the former Rangers manager thinks it is an "interesting" appointment that could work for both parties.
"Steve G's status is obvious - one of the best Premier League midfielders," he added.
"He has played and worked under some outstanding managers, so his pedigree is there for all to see.
"Wherever he goes, he is going to attract media attention. It is a good opportunity."