Redknapp, who was confirmed as Mark Hughes' successor at the club on Friday, loaned and then sold Taarabt to QPR during his time in charge of Tottenham.
But the 65-year-old insists Taarabt can improve the fortunes of the club, who sit bottom of the table after picking up just four points from their first 12 games.
"Adel has a big future," Redknapp told the club's official website.
"He's an amazing talent with the ball. He can still do more without it, but there's no doubt he's a match-winner for us.
"He can turn things for us. He's the player who can do something special, so we'll be looking to get the best out of him.
"I never really wanted to sell him at Tottenham to be honest. I had a good relationship with him. I never had a problem with Adel.
"At times his problems were self-inflicted, but I let him go because he wasn't playing and the Chairman felt it was a good time to let him go.
"He was a player I was always wary of letting go because I knew he could come back and haunt me one day."