League sources told ESPN the Cavaliers and Clippers were "working through parameters" on Sunday for the exchange.
Sources told Cleveland.com Dekker is being acquired with the Cavaliers' $5.8 million trade exception that was created in the Kyrie Irving trade with the Boston Celtics. The swap also includes the draft rights to European players from both franchises.
Cavaliers forward/center Larry Nance Jr. tweeted a welcome message to Dekker on Sunday night, with Dekker responding "let's rock."
Dekker also referred to Cleveland in his Twitter bio and updated his avatar with Cavaliers team colors.
"Excited to get out the #TheLand and play with the dirtiest dude in the league," Dekker wrote, jokingly referencing Nance. "But for real, couldn't be more excited for the opportunity. I'm more than ready."
Sources told ESPN that the Cavaliers will not be trading a player back to the Clippers in the deal. The trade isn't expected to be finalized until Monday or Tuesday night, according to the report.
Dekker, 24, was the No. 18 overall pick in the 2015 NBA Draft. The 6-foot-9, 230-pound forward averaged 4.2 points and 2.4 rebounds per game last season for the Clippers. He started once in 73 games.
Dekker averaged 6.5 points, 3.7 rebounds and one assist per game during the 2016-17 season for the Houston Rockets, making two starts in 77 games. The Rockets traded Dekker, Patrick Beverley, Montrezl Harrell, Darrun Hilliard, DeAndre Liggins, Lou Williams, Kyle Wiltjer, cash and a 2018 first- round draft pick to the Clippers in June of 2017 in exchange for All-Star point guard Chris Paul.
Dekker is due $2.7 million during the 2018-19 season. He made $1.79 million during the 2017-18 campaign. He will be a restricted free agent next season.