The family band from Nashville, Tennessee, who played the Glasgow Hydro and BBC Radio 1 Big Weekend earlier this year, will be out of action while Followill recovers. But Ahmir "Questlove" Thompson is coming to the rescue for an appearance on The Tonight Show with Jimmy Fallon.
Thompson, the house bandleader, will sit in for the Followill, 35, on the song Family Tree.
The band is cancelling nine shows, including Sunday's missed gig in Saratoga Springs, New York.
Followill broke his ribs when the band's tour bus driver was forced to stop when a pedestrian crossed the street in front of the vehicle on Saturday night after KOL's show in Boston.
The Grammy Award-winning band will return to the stage on August 28 in Holmdel, New Jersey.