"We don't yet know the extent of the injury," Smith said Saturday.
Jenkins fell on his right shoulder during the Falcons' scrimmage the night before at a local high school.
It was the first time in training camp that Smith allowed tackling to the ground, though quarterbacks were off limits from hard contact.
Smith indicated that the team might provide details of Jenkins' injury on Monday.
Jenkins, who's entering his seventh year with Atlanta and his sixth as a starter, fell on his right shoulder after running a crossing route in zone coverage on a long incompletion. Quarterback Matt Ryan said he underthrew the pass.