Mills has played in a career-high 71 games this season, averaging 9.8 points and 1.8 assists per game.
"He changed his entire body," Popovich said. "He came back svelte and cut and understood you have to make better decisions, point guard type decisions. He did all those things better and he earned it. He's been real important to us, obviously."
The Spurs got to the NBA Finals last season, but a big effort from Mills in the playoffs this year could be what they need to finish this time for title No. 5.