The Spurs are 7-0 home, where they have also won seven straight against a Rockets team that comes to town with Dwight Howard for the first time.
Harden came back Friday after missing three games with a sore left foot and had a season-low nine points and seven assists in 25 minutes in a 114-95 home rout of Brooklyn.
Coach Kevin McHale said that the Rockets' top scorer would not have played had Jeremy Lin not been out with a sprained right knee. Lin is out for at least two weeks.
"I was happy to have him at 25 minutes," McHale said. "Our goal was under 30. Our big thing is to see how he feels tomorrow. Hopefully, that foot feels as good tomorrow as it did today."
Parker sat out Friday's 109-91 victory at Orlando with a sprained ankle. Spurs coach Gregg Popovich said there's a chance Parker will play Saturday.
''We'll see how he feels,'' Popovich said. ''His sprain wasn't severe.''
Parker averaged 24.5 points to help San Antonio (14-2) take three of four from Houston last season. Harden missed one of those contests, but averaged 30.3 in the others and also notably averaged 18.5 points in the Western Conference finals against San Antonio two seasons ago with Oklahoma City.
The Spurs have won nine of the last 13 meetings in this Texas rivalry that the Rockets hope will swing in their favor with the addition of Howard. He last faced San Antonio when his ignominious Los Angeles Lakers career ended in a first-round sweep in last season's playoffs.
Houston (12-5) has won a season-high four straight while getting a minimal contribution from Howard, who is averaging 12.3 points and 8.8 rebounds in that span.
"Everybody is learning how to still play together," he said. "We are 12-5 now. Again, we want to be a lot better team come February than we are now."
While the Rockets now must adjust to playing without Lin, the Spurs don't seem too worried about not having Parker on occasion. The Western Conference's best team got 19 points apiece from Tim Duncan and Marco Belinelli in cruising past the Magic.
''That's the way we are made,'' San Antonio's Manu Ginobili said. ''We don't depend on absolutely one player. If we were going to miss Tony for 20 games, that's another thing. But we can replace anybody for one or two games. We are deep. That's one of the strengths of this team.''
Ginobili offered his assessment of the Spurs in a similar vein to Howard's thoughts on the Rockets.
"You can't really think that you're going to start 14-2," Ginobili said. "But we know we have a good team. We know we're going to win 50 games. That's what happened last year, and I think we're a better team this year."
Houston's Chandler Parsons made all seven shots for 21 points Friday and is 21 for 27 from the field - including 9 of 14 from 3-point range - in his last three games. He averaged 17.8 points against the Spurs in 2012-13.