Cleveland is also sending its 2018 first-round pick and Channing Frye to the Lakers, league sources said.
Thomas, 29, returned from a hip injury on Jan. 2 to average 14.7 points, 4.5 assists and 2.1 rebounds per game for the Cavs. He is shooting 36.1 percent from the floor and 25.3 percent from 3-point range this season.
Thomas, a two-time All-Star who was an All-NBA player last season, will be a free agent this summer.
Clarkson, 27, is a dependable bench scorer who averaged 14.5 points, 3.3 assists and three rebounds in 52 games for the Lakers. He has two years and $25.9 million left on a four-year, $50 million deal he signed in 2016.
Nance, 25, is a high-energy forward who averaged 8.6 points and 6.8 rebounds in 42 games this season. He is in his third NBA season and is owed $2.2 million in 2018-19.
Frye, 34, is in his 13th NBA season and was playing 12.4 minutes a game as a stretch big man for the Cavs.
Cleveland is 31-22 and third in the East after going 5-5 in its last 10 games. The Cavs won a dazzling 140-138 overtime thriller over the Minnesota Timberwolves on Wednesday night, with LeBron James hitting the game-winning shot.
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