Leonard's 2017–18 season was overshadowed by an injury, and by ensuing disputes between Leonard and the Spurs regarding the handling of that injury. He missed the first 27 games of the season with a right quadriceps injury, making his season debut on December 12, 2017, against the Dallas Mavericks.  On December 26, 2017, in just his fifth game of the season, Leonard scored a season-high 21 points on 8-of-17 shooting in a 109–97 win over the Brooklyn Nets.  On January 2, 2018, he set a new season high with 25 points in a 100–91 win over the New York Knicks.  Three days later, in a game against the Phoenix Suns, Leonard suffered a partial tear in his left shoulder.  He returned to action on January 13 after missing three games and scored 19 points in a 112–80 win over the Denver Nuggets.  Four days later, however, he was ruled out for an indefinite period of time to continue his rehabilitation process from right quadriceps tendinopathy.  Leonard was subsequently cleared to play by the Spurs medical staff, but he solicited a second opinion from his own doctors.