Rooney insists Slot lacks the "aura" to be successful at Liverpool long-term.
"It's strange isn't it when you're talking about Slot being on an audition to keep his job when he has obviously recently won the Premier League," he said on The Overlap Fan Debate.
"I have met him a couple of times, but I just don't think, for Liverpool, he has that aura – and maybe that's because Liverpool have just come off the back of Jurgen Klopp as manager – it's difficult for anyone to do that but I just don't think there is that aura about him."
Rooney added, "I have spoken to managers, and I know they can be difficult at times, but if he doesn't get them top five in the Premier League, he will be gone, for sure. It's crazy to say when he has just won the Premier League."