Lewis has one year and $22 million remaining on the blockbuster contract he signed with the Orlando Magic in 2007. He turns 33 in August and has played 13 NBA seasons since entering the NBA as a high school player in 1998.
His contract includes a buyout of approximately $14 million.
Ariza, a small forward who played well in a supporting role with the Lakers and emerged in the 2009 playoffs, didn't become a star after signing as a free agent with the Rockets in July 2009. But he is just 26, has two years and just under $15 million remaining on his contract and fills a need for the Wizards.
Okafor, the former No. 1 overall pick, has two years and $28 million left on his current deal. He averaged 9.9 points and 7.9 rebounds last season with the Hornets but played in just 27 games.
However, both players can use their early termination option to become free agents after the 2012-13 season.