In his last outing for Double-A Tennessee on Saturday, Garza threw 66 pitches over 3 1/3 innings.
"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."
"It's only going to get better when we get him back here," Cubs pitcher Jeff Samardzija said. "Obviously, we want him to be healthy, and that's the most important thing."
Carrie Muskat is a reporter for MLB.com. She writes a blog, Muskat Ramblings, and you can follow her on Twitter @CarrieMuskat. This story was not subject to the approval of Major League Baseball or its clubs.