Coach Gus Bradley said Monday that he didn't expect either player to play and neither practiced this week.
Gabbert suffered a strained left hamstring during the third quarter of the Jaguars' 34-20 loss to St. Louis last week. He has already missed two games this season because of a severe cut on the back of his right hand, and he missed the final two preseason games with a fractured right thumb.
Gabbert has completed 49 percent of his passes for 481 yards and one touchdown. He has thrown seven interceptions, three of which have been returned for touchdowns. His status for next week's game against San Diego is uncertain.
Chad Henne will make his third start of the season.
Lewis has been battling a calf injury, which he originally suffered during warm-ups prior to the second preseason game. He aggravated the injury before the season opener and missed the first three . He returned to the lineup against Indianapolis on Sept. 29 but lasted just two plays.
Bradley said he's unsure of when Lewis will be able to return.
"He's made really good progress the last couple days," Bradley said. "I think his leg feels better. We're still not going to say, hey, he should be back here or there, but [he has made] really good progress and I know mentally he's in a good state right now."
Receiver Cecil Shorts (groin), whom Bradley held out of practice Thursday as a precautionary measure, practiced Friday and will play Sunday. Shorts leads the Jaguars with 31 receptions.