Popovich stayed home sick and Duncan sat on the bench with a sore left knee Wednesday night during San Antonio's 106-102 victory against New Orleans. Longtime assistant coach Mike Budenholzer will again take the helm against the Mavericks.
Duncan is having a resurgent season after a few years of waning production. The 36-year-old is averaging 17.5 points and 9.8 rebounds, his best numbers since 2009-10.
The Spurs have won six straight and are tied with Oklahoma City for the best record in the Western Conference.