Thompson was selected fourth overall by the Cleveland Cavaliers in the 2011 NBA Draft. He was the highest-drafted Canadian-born player in NBA history at the time (until Anthony Bennett and Andrew Wiggins were selected for the first picks overall in 2013 and 2014.) During the 2011 NBA lockout, Thompson attended classes at the University of Texas to complete his bachelor’s degree. On December 9, 2011, just before the start of training camp, he signed his rookie contract with the Cavaliers. Thompson made his professional debut in December 2011 against his hometown Toronto Raptors. He scored 12 points and grabbed five rebounds in just seventeen minutes off the bench. Tristan finished the season with averages of 8.2 points and 6.5 rebounds in 60 games, and he was named to the NBA All-Rookie second team, making him the first Canadian to do so.
During the 2013 offseason, he decided to switch his shooting hand from left to right. Despite the change, he started all 82 games and finished tied for fifth in the Eastern Conference with 36 double-doubles, a team-leading, and career-high. The Cavaliers acquired LeBron James during the 2014 season. Thompson came off the bench for the majority of the season, solidifying his status as one of the league’s best offensive rebounders. That season, Thompson and the Cavaliers made it to the NBA Finals for the first time.
