Brantley was carted off with an apparent leg injury during Thursday's practice, Mary Kay Cabot of The Cleveland Plain Dealer reports.
Though he had to be helped to his feet by trainers and was subsequently carted off, coach Hue Jackson later said Brantley may have just had some cramping, though the official diagnosis has yet to be provided. The 23-year-old defensive lineman played in 12 games last season and is slated to back up Trevon Coley.