The much-traveled Hamilton, 36, was in training camp with the New York Jets this summer, but was released before the start of the season. Financial details of Hamilton's contract were not available.
Although he had some workouts during the season, and a few overtures from other teams, Hamilton has not played at all in 2007. But given his familiarity with Crennel's scheme, and the Browns' need for defensive line depth, he could play this weekend in a reserve role.
The Browns conclude the regular season by hosting San Francisco on Sunday afternoon. Cleveland will earn the final AFC wild card berth only if Tennessee loses at Indianapolis on Sunday night.
Hamilton has played with three different franchises, including two stints with the Jets, during his NFL career. The former Southern Mississippi star, who has spent most of his career playing in a 3-4 front, has always been a solid defender against the run.
In 164 career games, 102 of them as a starter, Hamilton has 478 tackles, 19 sacks, two forced fumbles, four fumble recoveries, one interception and 28 passes defensed. With the Jets last season, Hamilton appeared in all 16 games and posted 30 tackles. He has played with the Jets (1996-99, 2006), New England (2000-2003) and Oakland (2004-2005). Hamilton worked under Crennel during his first stint with the Jets, then later with the Patriots.
For salary cap reasons, Hamilton was released by the Jets on March 1, then re-signed for camp. But he failed to earn a roster spot and was released at the end of preseason.
Cleveland on Wednesday also elevated defensive lineman Mel Purcell from the practice squad to the active roster. The former Hawaii lineman was a sixth-round choice in the 2007 draft.
Len Pasquarelli is a senior NFL writer for ESPN.com.