Bishop suffered an undisclosed injury during Tuesday's practice and did not return, Maddy Glab of the Bills' official site reports.
The Bills already lost veteran Mike Edwards this week to a hamstring injury, and now the rookie from Utah will join him on the sidelines. Buffalo did bring in Kareem Jackson on a one-year deal Tuesday, so there is at least one reinforcement available for a secondary that already lost long-time stars Jordan Poyer and Micah Hyde this offseason.