Abreu, 34, has been ill since the weekend and didn't travel with the team to Houston on Tuesday. He'll be a game-day decision.
"He caught a bit of the flu," manager Tony La Russa said before a Wednesday workout at Minute Maid Park. "Got to the workout yesterday [in Chicago], and he had had a tough night with fever, and now we're all brimming with happiness and excitement because the fever broke.
"He passed the [COVID] test, which [is] mandatory, and he'll be flying back here tonight."
The White Sox also announced their Game 1 and 2 starters as Lance Lynn will get the ball first, followed by Lucas Giolito. It's a special assignment for Lynn, who broke into the majors with the St. Louis Cardinals when La Russa was the manager there in 2011.
"So it's been 10 years, and for me to have this opportunity with him is pretty special because he's -- I joked the other day -- he's the only manager to ever send me down," Lynn said. "So we have that going for us."
Lynn has been the Sox ace all season, compiling an 11-6 record and 2.69 ERA. Meanwhile, Giolito has been the best White Sox starter in the second half and pitched Game 1 of the playoffs last season against the Oakland Athletics. Lynn and Giolito will be opposed by Lance McCullers Jr. and Framber Valdez, respectively.
La Russa didn't name a Game 3 starter and held off on any postseason roster news regarding lefty Carlos Rodon. Rodon has been hampered by fatigue and soreness in his pitching arm. Teams don't have to submit their 26-man rosters until the morning of Game 1.
But the biggest concern surrounds Abreu, who drove in 117 runs this season. He's as important to the White Sox as anyone.
"I think he's the biggest key that we need healthy," shortstop Tim Anderson said. "But I'm sure you know, we all know, how stubborn he is, and you know he's not going to want to sit out. He's not going to be happy about that."