Garza, on the disabled list with a strained left lat sustained in a Spring Training workout on Feb. 17, will make his fourth Minor League rehab start on Thursday for Triple-A Iowa.
"I'm just going for the next one," Garza said Tuesday. "I'm looking forward to Thursday, and after Thursday, we'll make a decision. They want me to get stretched out and get deeper into games, and I guess that's what I have to do now."
He threw 66 pitches in his last outing for Double-A Tennessee, but it was over 3 1/3 innings. The Cubs want him to go deeper in the game.
"I've been throwing strikes, I've been working on things I need to work on," Garza said. "It's all piecing together. I feel fine and am excited about Thursday."
But who gets bumped when Garza is ready? Over the weekend, Cubs manager Dale Sveum said they weren't considering a six-man rotation. But on Monday, he said it could be a possibility.
"It's a tough decision, because everybody has pitched pretty well," Sveum said. "It's going to be one of those things that will be unfortunate for somebody, but it's a reality and it's going to happen."
Carlos Villanueva, who started Tuesday, has the most experience as a swingman.
"It might lean to who we're playing that series, the matchups," Sveum said. "Maybe you go to a six-man rotation for a week because of matchups. You never know what the bullpen is like. A lot of things come into play. We'll make that decision -- and I know you guys are going to keep asking this question every day. It's not going to change."
Travis Wood posted his eighth straight quality start on Monday, and has a 2.03 ERA. Scott Feldman has a 2.53 ERA in his seven starts, which include a complete-game win.
"I guess that's the best problem to have," Garza said. "I want to pitch. I'm not getting ready for no reason. The guys are doing great. I've got to really step into it and gear up for it. I'm excited to come back and champing. I'm not looking forward to anything past Thursday."
Does he have a say in the matter?
"I would say a lot, based on, it's my job," Garza said. "It comes down to what the organization wants to do. Obviously, we'll sit down and talk about it after the next outing. It's all based on how I respond and how I feel and how comfortable I am."