As part of the trade, the Cavaliers will send the draft rights to Vladimir Veremeenko to the Clippers. The Cavaliers will also receive the rights to Renaldas Seibutis and cash considerations.
The Clippers' trade of Dekker, who was acquired from the Houston Rockets in the Chris Paul deal in June 2017, allows the team to shed a much-needed roster spot before the start of training camp in late September.
"We want to thank Sam for his contributions to our team competitiveness and culture this past season," Clippers president Lawrence Frank said. "Sam is a talented and hard-working athlete who represented this organization well as a player and a person. We wish him the best of luck with his opportunity in Cleveland."
For Cleveland, the trade provides depth to the forward position with restricted free agent Rodney Hood still unsigned.
Dekker, a first-round pick by Houston in 2015, averaged 4.2 points and 2.4 rebounds as a reserve in 73 games last season for the Clippers. The 6-foot-9 Dekker figures to get more minutes with the Cavaliers, who are revamping their roster following superstar LeBron James' departure as a free agent.
Dekker starred at Wisconsin before he was taken with the No. 15 overall pick by the Rockets three years ago. He played in four postseason games for Houston in 2017, averaging 2.3 points and 2.5 rebounds.
The 24-year-old will earn $2.76 million this season and will be a restricted free agent next summer. The Clippers will now have a $2.8 million exception.
ESPN's Adrian Wojnarowski, Bobby Marks and the Associated Press contributed to this report.