The Black Cats are due to face Everton at the Stadium of Light later this evening, with Martinez under huge pressure.
The Spanish boss has faced calls for him to be sacked from supporters of the Merseyside club, with ‘Martinez Out’ banners being held aloft at many of Everton’s recent matches.
Allardyce says that Everton should stick by their manager, though, as they are yet to spend any of the money they have received from their new investor, Farhad Moshiri.
“I’m surprised that just because Everton are getting a new director who’s supposedly putting a few bob in over the summer that it says Everton suddenly have to be so much better,” Allardyce says. “If he has put any of that money in yet, they haven’t spent any (in the transfer market).
“We should all be allowed a disappointing season. Roberto should be allowed the time to overcome a disappointing season. Roberto should be defined by what he’s done in his career and what he’s done for Everton since he’s been there.”
Martinez was expected to guide Everton into competition for a top six place this season, but he has badly disappointed.
Everton’s defence has looked poor all campaign, and they are currently stuck in 12th position.
The Toffees have won just one of their last nine matches, and they could yet slip down to 16th place before the end of the season.
Sunderland will be determined to inflict further misery on Martinez’s side, as they can confirm their safety with a victory later this evening.