Austin was taken to Erie County Medical Center by ambulance following the 26-10 loss. The Browns say Austin, who has made several clutch catches for the club this season, is being kept for precautionary reasons. The team has not disclosed any other details of his injury.
Austin made seven catches for 86 yards against the Bills. His playing status remains unknown for this week.
Coach Mike Pettine is expected to provide an update on Wednesday.
The 30-year-old Austin is in his first season with the Browns, who signed him as a free agent in May. He spent the previous eight seasons with the Dallas Cowboys.