Leicester are at the top of the Premier League table at the moment with 69 points from 32 matches.
The Foxes are seven points clear of second-placed Tottenham Hotspur and are favourites to win the league title this season.
Claudio Ranieri’s side will take on Sunderland away from home in the Premier League next weekend.
Given that the Black Cats are fighting for survival in the English top flight, many will expect Leicester to pick up all three points from the encounter at the Stadium of Light.
Former Tottenham boss Redknapp, though, believes that it will not be easy for Leicester to win against Sam Allardyce’s side.
“On paper their trip to the Stadium of Light looks simple enough, but at this stage of the season I cannot think of many tougher teams to play than a Sunderland side fighting for their lives,” the Englishman wrote in The Telegraph.
“They are absolutely desperate for points and Sam Allardyce will have them well prepared. Sunderland seem to have been written off, too, and I really do not know why.”
“The stakes are huge for both teams,” added Redknapp. “Leicester will be doing really well to win that game, and I would not be shocked if they come unstuck.”
Sunderland could win against Leicester at home, but that should still not affect the Foxes’ title chances.
Give that Ranieri’s side have a seven-point lead at the top of the standings, they can actually afford to lose two Premier League matches between now and the end of the season.