Salah was again benched for the start of Wednesday night's 1-1 draw with Sunderland at Anfield.
The 33-year-old was brought on in the second-half but was unable to make a significant difference against the Black Cats.
"He's a Premier League great, a Liverpool great and that's why I don't think this is going to end well," Redknapp said on Sky Sports. "It will be a difficult situation now because the manager, when you've got someone who is so good, so important to the team, in and around the dressing room and how they react and act in training.
"He's not going to want to be on the bench, he hasn't signed this contract to see his career out. He wants to play week in, week out.
"I'll be amazed if he sees out the last two years of his contract, or year and a half. I don't think this helps the situation one bit. Nothing will surprise me in football - whether it's in January or maybe in the summer.
"If the right club was to come around... a lot will be decided by this man. He's earned that right. And if he says: 'Look, if I'm not going to be a starter for you, I'm not one of those players who is going to hang around. I will go wherever it takes.' I still feel he will want to play in Europe.
"The first thing we're all going to say is he'll go to Saudi - he's obviously a legend in that part of the world - or he'll want to go to the US, but this for me now is a real breaking point in the relationship.
"He'll feel let down and, like you say, maybe even blamed for what's going on. But while the team is winning without him... I saw those stats and they're pretty good when he doesn't play.
"No one is indispensable, time waits for no one, and it's going to be difficult now."