McKenzie (undisclosed) isn't participating in practice Tuesday, Josh Reed of WIVB reports.
Joe Buscaglia of The Athletic reports McKenzie left practice early Saturday. It doesn't sound serious, but with Week 1 approaching he'll be on a tighter schedule now. McKenzie worked ahead of Jamison Crowder as Buffalo's No. 3 receiver this preseason, but both could have roles come Week 1 against the Rams.