The Jaguars announced the move on Sunday morning.
"Leonard Fournette is not playing in today's game due to an infraction of a team rule," Jaguars coach Doug Marrone said in a statement. "This has been addressed internally and further details will not be made public."
The Jaguars host the Cincinnati Bengals at 1 p.m. Sunday at EverBank Field.
Veteran running back Chris Ivory will start in Fournette's place.
Jaguars right guard A.J. Cann is out with a triceps ailment. Center Brandon Linder returns from an illness to start at right guard for Cann.Tyler Shatley will start at center. Wide receiver Marqise Lee and and Cam Robinson will be active and start.
T.J. Yeldon and Corey Grant are in line behind Ivory for carries Sunday against the Bengals, a team allowing the ninth-fewest fantasy points per game to opposing running backs.
This is a huge blow to Fournette's fantasy football stock owners. The rookie ranks No. 1 in rushing yards per game for full-time starting running backs. Yeldon actually ranks No. 1 in the category, but only has nine carries.
Ivory is an RB2 against this defense.