Kyle Anderson will take Leonard's place in the starting lineup.
A four-year veteran, Leonard is averaging a career-high 20.2 points to go with 6.7 rebounds and 2.5 assists, and he's shooting 51 percent from the field and 48.2 percent from 3-point range.
Leonard's injury comes on the heels of the team welcoming back forward Tim Duncan, who had missed eight games because of soreness in his right knee. Duncan returned to the lineup on Feb. 10 in the team's 98-86 win over the Orlando Magic.
San Antonio is also without veteran guard Manu Ginobili, who is recovering from testicular surgery and expected to return in approximately three weeks.