Lennon was infamously pictured smoking a cigar during a boozy get-together at the team hotel hours after the thrashing by Germany.
Redknapp claims the only person who can get him out of his recent dip is the 23-year-old himself.
He said: "I never saw that picture of him. Someone told me he had a big cigar in his mouth. If he smokes too many of those he'll lose his speed and then he'll be in trouble!
"But seriously, I talk to him about his game all the time and I've never spoken to him about that incident.
"He was flying last year, but he's certainly not playing like that now, that's for sure. It's getting harder and harder for him in that position."