Knox (undisclosed) didn't participate in Tuesday's mandatory minicamp practice, Alaina Getzenberg of ESPN.com reports.
Bills head coach Sean McDermott said Knox was dealing with a minor injury during OTAs, so it appears his extended absence is merely precautionary. The 2019 third-round pick caught a career-high nine touchdowns last season, but he may face competition for targets in 2022 from the recently signed O.J. Howard.