Brown hurt his right ankle during an opening win at Indianapolis on Sunday and had been listed as questionable. The Bengals also are missing linebacker Vontaze Burfict, suspended for the first four games for violating the NFL's policy on performance-enhancing substances.
Backup tackle Cedric Ogbuehi — a first-round pick in 2015 — also is inactive for Cincinnati.
There are no changes in the Ravens' starting lineups. Quarterback Lamar Jackson played in their opening win over the Bills and is Joe Flacco's backup again. Robert Griffin III is inactive for the second straight game.