It was, Rodgers said, a string of black nightclubs that stretched from Buffalo, New York, to South Florida. The audiences could be demanding but, without the circuit, he added, there would be no Hendrix, no Marvin Gaye, no Commodores.
And now, it seems, there might have been no Steven Seagal, blues musician, either.
Surprisingly for those who know him only through his action-movie roles, Seagal has a long, long history of being steeped in the blues. He grew up with the genre - "the blues is in my soul", is how he puts it - and he has in the past jammed with such illustrious names as BB King, Bo Diddley, John Lee Hooker and Clarence 'Gatemouth' Brown.
He returns to Glasgow tonight for the first time since January 2007, when he played five sold-out concerts at The Ferry.
The Herald briefly caught up by telephone with Seagal somewhere in Belgium. He is in the middle of an European tour that had already taken him to Slovenia, Serbia, Bulgaria and Germany. The show at The Ferry is his only Scottish engagement.
How has the tour gone so far? "I think it's been amazing, everywhere we go," he says.
He was born in Lansing, Michigan, in April 1952. From an early age he was pre-occupied with the martial arts and the blues. When he was five, the family re-located to California.
He grew up listening to the blues. Their influences went marrow-deep: Muddy Waters, Howlin' Wolf, BB King.
His mother bought him his first guitar when he was 12. He gigged with local bands and, in clubs and bars, jammed with some of his heroes. He was nervous when he sat in with BB King, but it was an important step in his blues education.
"In Michigan," he said, "I just played with everybody on the porch and learned how to play the blues.
"By the time I started going out on what I would call the chitlin' circuit, it was more places like Texas, Louisiana, Mississippi, Alabama, those kind of places."
We put to him Nile Rodgers' description of the chitlin' circuit. Is that how he remembers it?
Yeah, he says. "There are several different kinds of quote-unquote chitlin' circuit.
"The original, of course, was all black, but there were tours where someone like me would be in an all-black band, which was a lot. They were just very, very hard circumstances, you know? Did I have to toughen up? That's for sure."
He talks about his backing band, Thunderbox, having to be slimmed down for certain club dates. "We have a festival band and we have a club band, so we're now transitioning from the band we had at festival dates at the start of the tour to a smaller, more intimate band for smaller venues."
His long-awaited third album, he adds, "is just about finished. On it there's me, Vinnie Colaiuta, David Lindley, Abe Laboriel - some real great musicians, and just some real cool, old, old blues and country-type songs, which I have written."
At The Ferry, meanwhile, they still remember Seagal's debut there.
The venue's Frank Taylor recalls that he was due to play just one date there, but as word spread that a bona-fide movie star was playing Glasgow, more dates had to be added.
What began as just one show suddenly became five - two gigs on each of two nights, and a final show on a third night.
Taylor said: "I don't think he had ever set foot in Scotland before those concerts, in January 2007. Everybody wanted to see him, and in an environment - music - that not too many people knew he was involved with."
Seagal sold out all five gigs, each to a capacity audience of just under 600, who relished his take on the blues and the songs from his then-latest album, Mojo Priest.
Observed The Herald's man-on-the-spot: "Operating in an area between Stevie Ray Vaughan and Tony Joe White, Seagal had the chops and the voice to carry it all off with considerable authority."
Seven-and-a-half years later, the big man is heading here again. It should be quite a night.
Steven Seagal plays The Ferry, Glasgow, tonight at 8pm.