Modric, the £16.5million summer signing from Dinamo Zagreb, had struggled to make an impact and looked lightweight until Redknapp's arrival.
"I felt that's his position, behind the front man," Redknapp said. "That's where he needs to play so that's where we decided to play him against Bolton.
"If you give him the ball, he'll do special things and has got great awareness. And he mucks in as well."