Garza, who is recovering from a lat injury, needed 75 pitches to get through six shutout innings for Triple-A Iowa on Thursday night, striking out six and walking none. He retired 13 of the last 14 batters he faced.
"We'll see how he does when he comes in," Sveum said Friday. "Then we'll talk about it (Saturday) morning after his side and see where we are."
Garza told the Des Moines Register he's ready for the big leagues.
"I don't need another one here," Garza said Thursday. "They might differ on opinion, but I think all in all, it comes down to what I want and the way I feel. The organization -- they're going to make the call at the end of the day but I think we're going to collaborate and come to some sort of compromise."
Sveum was asked if durability was an issue considering six innings is the longest he's pitched in any rehab start.
"Durability is about the last thing we have to worry about with him," Sveum said. "He's pitched so much, thrown so many long sides. He's built up to have durability."
An elbow injury sidelined last July and a lat problem on his left side which occurred early in spring training this year has kept him out. He'll be a free agent after this season.
"They wanted me to piece everything together," Garza said. "They told me what I needed to do and I accomplished what I needed to do."
Sveum said he hasn't told any of his current starters they're going to the bullpen when Garza returns but Cubs brass has discussed options internally. Previously, Sveum said a six-man rotation could be an option for a short time but pitcher Carlos Villanueva remains the top candidate to pitch in relief when a decision to activate Garza is made.
Garza is due back in Chicago Friday afternoon.