McKenzie, who logged a limited practice Thursday, remains in the concussion protocol, per coach Sean McDermott, Alec White of the Bills' official site reports.
McDermott noted that McKenzie is in a day-by-day process ahead of Sunday's game against the Steelers, though Alaina Getzenberg of ESPN.com relays that the Bills' slot man shed his red non-contact jersey at Friday's practice. While that's encouraging, the team's upcoming injury report will add further context with regard to McKenzie's Week 5 status. If he's out or limited this weekend, Khalil Shakir would be in line for added snaps behind top wideouts Stefon Diggs and Gabe Davis.