Knicks coach Mike Woodson says Smith, the reigning Sixth Man Award winner, will come off the bench.
"We've just got to make sure that mentally he's there," Woodson said. "And I can't burn him physically."
Smith underwent surgery in July to repair his left patella tendon and a lateral meniscus tear in his left knee and Woodson will limit his minutes to around 30 against San Antonio.
Smith said on Saturday that he still lacks explosiveness in his knee and needs to work on his conditioning.
"I have good days and bad days," the 28-year-old said.
Smith re-signed with the Knicks in July, inking a three-year, $18 million contract. He raised eyebrows around the league by electing to have surgery a week after signing his contract rather than earlier in the offseason. The timing of the procedure caused Smith to miss most of training camp. He played in the Knicks' final preseason game and began serving his suspension in the season opener.
"I can't wait (to return)," Smith said on Saturday. "I'm anxious more than anything. I just want to do so well for my teammates."
Smith should help boost a Knicks offense that ranks 17th in efficiency (points scored per 100 possessions.
He should also provide a scoring punch for the Knicks' second unit. Last year, Smith averaged 18.1 points, 5.3 rebounds and 2.7 assists to earn his first career Sixth Man Award. He struggled in the playoffs though, hitting just 33 percent of his field goals. He was also suspended one game for elbowing Boston's Jason Terry in the face.
Smith blamed himself for the Knicks second-round loss to Indiana but said on Saturday he's no longer fixated on his playoff struggles.
"I really try to leave last season in last season and try to treat every year as a new year," he said. "You can't really hold grudges."
There's a chance Smith will end up in the starting lineup as the season progresses. Woodson has said Smith and Iman Shumpert will battle for the starting shooting guard position.
But with Tyson Chandler sidelined for 4-6 weeks with a fractured right fibula, it makes the most sense for Smith to come off the bench at the moment. Andrea Bargnani is starting at center in place of Chandler so the Knicks need Smith's scoring off the bench.
Woodson will start Raymond Felton, Pablo Prigioni and Shumpert alongside Carmelo Anthony and Bargnani on Sunday against the Spurs. That lineup helped the Knicks to a 101-91 win over Charlotte on Friday night, improving them to 2-3 on the season.
"I liked what we saw (Friday), so we're going to roll with that again (Sunday) and see where we are," Woodson said.