Ben Roethlisberger took the other 15 percent and looked good enough to play, according to a source, but was inactive for Sunday's game. The untested Tyler Murphy will be the backup against the Kansas City Chiefs.
Meanwhile, for the Chiefs, receiver Jeremy Maclin was inactive for Sunday's game despite clearing the NFL's concussion protocol and returning to practice Friday.
Roethlisberger has missed the past three games with a sprained MCL and bone bruise to his left knee and would have had to wear a knee brace if he had played. He's never worn a knee brace in an NFL game.
Sunday's absence marks the first time in Roethlisberger's career that he's missed four consecutive games because of injury.
The Steelers' quarterback situation is further complicated because backup Mike Vick is out with a hamstring injury. Murphy took scout-team reps this week and was promoted from the practice squad Saturday to provide coach Mike Tomlin options if the coach decided against having Roethlisberger active.
Jones passed for 168 yards and two touchdowns last Sunday in relief of Vick to rally the Steelers past the Arizona Cardinals.