Coach Jack Del Rio said Wednesday that Garrard has a high ankle sprain, meaning he has ligament damage, and will sit out road games against Tampa Bay and New Orleans.
"It's more likely to be three or four (games), somewhere in that window," Del Rio said. "I don't think it's likely to think he'll be back any sooner than that."
Del Rio said Quinn Gray will make his first career start against the Buccaneers on Sunday. The Jaguars also planned to work out Doug Johnson, Drew Henson and Todd Bouman later Wednesday.
Drew Bledsoe was approached about a tryout but declined to come out of retirement.
Garrard injured his ankle in Monday night's 29-7 loss to Indianapolis. He tried to play through the injury, but his ankle swelled up considerably at halftime.
Gray struggled in his second extensive playing stint in the last two seasons. He finished 9-of-24 for 56 yards, with two interceptions and a fumble.
"We've got to rally around Quinn," Del Rio said.
Garrard could miss 4 games with injury
Jags Illustrated Top Stories
Paper Weight: An Interview w/ Allen HurnsJaguars WR Allen Hurns earned a 4 year $40 million contract this past offseason, $20 million of which is guaranteed. A lot of players might fold under the pressure of their first…
Jags Illustrated3:20 PM
The Great EscapeThis team needs to get out of town. Out of the state. Out of the timezone. Out of the hemisphere. Okay not quite that far, but almost.
Jags IllustratedYesterday at 6:38 PM
London's Gentleman: Roy Miller InterviewI sat down with Jags DT Roy Miller in the locker room. We discussed everything from Gus Bradley's future to the trip to London.
Jags IllustratedYesterday at 7:00 AM
Identity CrisisThe Jags have started the 2016 season on a rough note. 0-3 is a tough pill to swallow and many fans are calling for Gus Bradley’s job. People are even starting to question their…
Jags IllustratedTuesday at 3:48 AM