Redknapp returned to Fratton Park this week a year after controversially taking a post at Pompey's south-coast rivals Southampton.
Pompey have struggled this season and Redknapp walked back into the hot seat with his side in the bottom three of the Premiership table - that turned into bottom two after Birmingham's win against Fulham.
Michael knows Redknapp well from his days at West Ham - he was the manager that brought the midfielder through the ranks at Upton Park."I think he'll certainly lift them, he has that presence about him and I'm sure we'll find in January that he'll get a couple of players in who will look to make a big impact," reasoned Michael.
"If you can get a few results when you are down there it gives you the confidence and belief to go on and get more and that's what Harry's about. A different atmosphere around the club could change things as well.
"Harry knows what he wants to do and wants to achieve and he'll see it as an opportunity to go back there and get them out of trouble."
Asked if Redknapp's return signalled danger for us on Monday, Michael responded: "We're at the stage now where we're not worried so much about who we're playing, the confidence and belief is strong enough for us to cope with whatever is thrown at us.
"They will be looking to impress a new manager but it's up to us to go out, play our game and win it."
Ledley King believes the spotlight being placed firmly on Portsmouth tonight - after the return of Harry Redknapp - could work in our favour.