Garrard returned to practice Saturday after missing more than a week of training camp. He threw passes during the team's morning walkthrough and was expected to take repetitions with the first-team offense Saturday evening.
"I'm tired of sitting around and watching," Garrard said. "But I'm not going to try to overdo myself with too many extra things."
Garrard, 33, left practice Aug. 4 because of back pain and could barely walk the following day. He spent the past week working with team trainers, but sat out Thursday night's preseason opener against the New England Patriots. Rookie Blaine Gabbert started in his place and had an up-and-down debut, going 9-for-16 for 85 yards.
Garrard made the trip and helped Gabbert from the sideline. Garrard wanted to play, especially because he missed the 2010 season finale because of a finger injury.
"It's been a while since I've been out there under the lights with the fans yelling," Garrard said. "It was frustrating to a certain extent, but it's still preseason. I didn't get too bent out of shape."
Garrard said he has a disc injury, more serious than muscle tightness. Nonetheless, he felt he could have played with a painkilling shot. However, that's something he hopes to avoid this season and down the road.
"That's such a scary thing to shoot yourself up and numb the pain so you can go out there," Garrard said. "I don't want to be like some of these guys you see that are retired and come back and can barely stand up straight."
Garrard said team doctors told him his back X-rays looked like those of some offensive linemen. Garrard has been sacked 117 times the past three seasons and been knocked down countless more times between running plays and pocket pressure.
Garrard has dealt with back pain throughout his career, but nothing this severe. He said he first starting feeling back pain during summer workouts. The pain settled down, so he didn't visit a massage therapist or a chiropractor. His back tightened up significantly last week, forcing him to leave practice on a golf cart.
"I know he's getting better," Del Rio said. "I'm going to stick to seeing is believing and we're hopeful. So we'll let those things play out. I'm not going to get into predicting when things may occur."
Garrard, though, expects to be ready for Friday's game.
"If I'm out here practicing, then I bet I'm playing," he said. "That's kind of my thoughts."
The Associated Press contributed to this report.