He took part in the team's workout Saturday morning and went full speed in a one-on-one workout with Bucks assistant coach Sean Sweeney afterward.
"It feels great just going out there, just playing, testing it, doing full speed," Antetokounmpo said. "I've just got to evaluate it tomorrow and then we'll make a decision."
Milwaukee has gone 3-2 without Antetokounmpo, the league's fourth-leading scorer, this season. With him unavailable Friday, interim coach Joe Prunty gave Jabari Parker his first start of the season and also moved forward Sterling Brown into the starting five.
"You're always trying to figure out what the best opportunities and options are going to be," Prunty said. "So we're prepared. You make your plans, then it's kind of like a game-time adjustment. And then you have your in-game adjustments."
Even if Antetokounmpo is ready to go, the Bucks will have to bring their defensive A-game to keep forward LaMarcus Aldridge in check. He was averaging 22.7 points per game entering San Antonio's game Friday night at Utah and exploded for a career-high 45 points, with 28 coming in the first half.
"He's been a horse all year long," Spurs coach Gregg Popovich said. "He was awarded that All-Star position, which he deserves, and he's basically carried us; him with his talent, and everybody else with their heart.
"The game goes along and goes along, and then you realize his heart is as big or bigger than anybody's. He's on the board getting rebounds, putting the stuff back, blocking shots, doing a little bit of everything that we have to do to win games."
At 43-30, the Spurs sit sixth in the Western Conference, 1 1/2 games behind Portland for the No. 3 seed.
"Unexpected, to tell you the truth," Spurs veteran Manu Ginobili said of the team's recent success. "Not that we aren't optimistic. But the way we were playing, we were a little demoralized, and a little down. We knew this six-game stretch was huge for us.
"We got to a point after the road trip in which we felt like we touched bottom, that we really had to get it together, to support each other, to fight every possession because if not we were out. We put ourselves in good position again, and now we just have to build from there."
The Bucks have won their last two meetings with the Spurs, marking the first time since 2008 that they've beaten San Antonio in consecutive games. A victory Sunday would mark Milwaukee's first series sweep of San Antonio since the 2008-09 season.