"He was sort of holding a clipboard," Sabol says of Graham when the pro football filmmaker hired him to do voiceover work in 2003.

Graham, who also hosts Baseball This Morning on Sirius XM Satellite Radio, officially becomes a first-stringer Wednesday as he takes the spot on Inside the NFL held for 32 years by his friend and former broadcast partner with the Philadelphia Phillies, the late Harry Kalas.

"It would be easy to look at it and say there were very big shoes to fill," Graham told USA TODAY. "But they can't be filled."

If Graham has any trepidation, Sabol doesn't. He's pegged Graham as a perfect replacement for Kalas to narrate highlights for the weekly show.

Sabol calls Graham's voice "distinctive but … not distracting," making it a good complement for NFL Films' multi-faceted pieces produced at the company's Mount Laurel, N.J., headquarters.

"The music, the natural sound and the pictures … it's the balance of those ingredients that's important … and the narrator's voice has to blend with all those ingredients," says Sabol, the video mixologist.

"It's like a good martini. Our narrator is the olive in that martini."

Graham will team with James Brown, Cris Collinsworth, Phil Simms and Warren Sapp, with Bill Cowher weighing in as guest analyst, as the program's 33rd season — and second on Showtime — marks its season premiere at 9 p.m. ET/PT.