Johnson, 31, spent the last five seasons with Buffalo. He notched 19 tackles and two sacks in 14 games as a reserve in 2012.
Johnson (6-3, 304) has primarily been a backup throughout his career, but he started 11 games two seasons ago for Buffalo. He’s notched 303 tackles and 14 sacks in nine NFL campaigns. In New England, he would likely provide an experienced option behind Kelly and Vince Wilfork if added to the roster.