"I don't know the extent of it, but I think we'll know first thing in the morning," Falcons coach Mike Smith said. "We're encouraged by what we saw on the sideline there."
Jenkins, one of 11 offensive starters returning this season, fell hard to the ground on a long incompletion that Matt Ryan appeared to underthrow.
"I just kind of missed him," Ryan said.
Jenkins, a Falcons starter since 2005, stopped short of the 30-yard line and stepped upfield a couple of yards to try to catch the pass on Ryan's play-action fake to running back Jason Snelling.
The ball was thrown into zone coverage as Jenkins ran a left-to-right crossing route. Neither Smith nor Ryan indicated whether Jenkins might have run the route too deep.
Jenkins arose slowly and walked gingerly to the sideline to see the trainers.
"He's the only guy we're listing on our injury report," Smith said.
The Falcons, whose preseason opener is next Friday against Kansas City, already planned no more live tackling drills over the next five days of training camp. Jacksonville is visiting Atlanta's complex in Flowery Branch for two days of practice next week.
Smith stood behind the offense throughout the scrimmage and watched as running backs Snelling and Dimitri Nance each ran for short touchdowns.
Third-string quarterback John Parker Wilson stepped up in the pocket to avoid pressure and hit running back Antoine Smith for a long TD down the right side.
The Falcons announced that a crowd of approximately 12,200 attended the free event at North Gwinnett High School.