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
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