Houston Rockets (2019–2020)Westbrook reunited with former Thunder teammate James Harden in Houston.
On July 16, 2019, Westbrook was traded to the Houston Rockets for All-Star Chris Paul, two protected first-round picks and other draft considerations. The move reunited Westbrook with former teammate James Harden; they both expressed mutual interest and enthusiasm in playing together at this stage in their careers. Harden spent his first three seasons in the league (2009–2012) on the Thunder with Westbrook, and prior to playing in Houston, they last played together in the 2012 Finals.
Westbrook made his Rockets debut in a 117–111 loss against the Milwaukee Bucks on October 24, 2019, leading the team with 24 points, 16 rebounds, and seven assists in 33 minutes of play. He joins Hakeem Olajuwon as the only Rockets players in franchise history to put up at least 20 points, 15 rebounds and five assists in a season opener. In Westbrook's second game as a Rocket on October 26, 2019, he became second all time in career triple-doubles, passing Magic Johnson with a 28-point, 13-assist, and 10-rebound performance in a 126–123 win against the New Orleans Pelicans. On December 7, 2019, Westbrook got his third consecutive triple-double with 24 points, 14 rebounds, and 11 assists on 10-of-18 shooting after going 14-of-57 in the previous two games. In this game, he passed Tony Parker for 18th in the NBA all-time career assists list. On January 3, 2020, Westbrook became the third player in NBA history with 19,000 points, 6,000 rebounds, and 7,000 assists after a 20-point, 7-rebound, and 4-assist performance.
On January 9, 2020, Westbrook made his return to Oklahoma City for the first time as a visitor, getting 34 points, 2 rebounds, and 5 assists on 14-of-26 shooting from the field in the 113–92 loss. With his triple-double against Oklahoma City on January 20, he joinged Lebron James as the only two players to have logged triple-doubles against all 30 NBA teams. On January 24, Westbrook scored a season-high 45 points on 16-of-27 shooting from the field, along with 10 assists and 6 rebounds, in a 131–124 win against the Minnesota Timberwolves. In the month of February 2020, he had 33.4 points per game, 7.3 rebounds per game, and 6 assists per game in addition to 54.9% field goal shooting and 40% three-point shooting. In that stretch, the Rockets went 7–1.
The NBA season was suspended beginning in March due to the COVID-19 pandemic. In July, Westbrook tested positive for COVID-19, but he recovered and was able to join his team later that month in Orlando, Florida, for the league's restart. In their third game back, Westbrook strained his right quad and missed four of the five remaining regular season games. He missed the first four games of the opening playoffs series against Oklahoma City, which was tied 2–2. He helped Houston advance to the semifinals, where they were eliminated 4–1 by the Lakers. In his eight playoff games, Westbrook averaged 17.9 points, 7.0 rebounds and 4.6 assists per game, the worst of his postseason career.