Gardner-Johnson was carted off the field to the locker room during Saturday's training camp practice due to a right lower-leg injury, Matt Parrino of The Syracuse Post-Standard reports.
Gardner-Johnson had to be helped into the medical tent after the injury before being taken back to the locker room, where he'll undergo further tests to evaluate the severity of the injury. The 28-year-old signed a one-year contract with the Bills in March in what was a significant upgrade to the team's secondary, so an extended absence would be a blow to Buffalo's defense. Gardner-Johnson was replaced by Geno Stone in team drills.