For Williams, Detroit sent a fifth-round pick in April's draft to the Browns in exchange for the tackle and a seventh-round choice.
Williams was drafted by Green Bay in 2004 and played his first four seasons with the Packers before being traded to Cleveland for a second-round pick in 2008.
Willliams is expected to return to the role he played the Packers, which allowed him to play a more aggressive style which is commonly called a three technique.
The Packers designated him as a franchise player in 2008 but traded him to the Browns for a second-round draft pick.
Williams could also be part of a revamped defensive front-four for the Lions and would free them up to select Nebraska's Ndamukong Suh over Oklahoma's Gerald McCoy if both defensive tackles are available at No. 2.
Suh is considered by many NFL evaluators to be more versatile along the defensive front. The Lions also have not ruled out trading down a few slots to collect an extra draft pick and still land another impact player, either on defense or the offensive line.
Williams made 18 starts in two seasons for Cleveland, but wasn't happy in coach Eric Mangini's 3-4 defensive system last season.
The Browns still have 11 picks this year, nine in the first five rounds.
Information from The Associated Press and ESPN senior NFL analyst Chris Mortensen was used in this report.