Johnson was an unrestricted free agent after signing a one-year deal last season. At the age of 28, Johnson provided leadership and run-stopping ability to a Bengals defense that was one of the surprises of the NFL.
A former second-round choice of the Bears in 2004, Johnson played three seasons for the Bears and two seasons for the Cowboys before joining the Bengals.
He started 13 games for the Bengals last season and had 29 tackles and two sacks.
Senior NFL writer John Clayton covers the NFL for ESPN.com.