The scratch was a setback in Garza's return from a strained left lat sustained on Feb. 17.
Chicago will see how long toss goes before scheduling a bullpen session for Garza and then ultimately another rehab start.
When asked if Garza would get another start within a week, Sveum said, "I would imagine."
Garza has not pitched in a Major League game since July 21, 2012, against the St. Louis Cardinals.
Sveum feels Garza could give his rotation, already a strength of the club, a major lift whenever he is able to come back. Cubs starters have posted a 2.97 ERA, which is tied for second-lowest in the National League with Atlanta, behind the Cards.
"When you get one of the better pitchers back in the National League in a rotation that's already obviously throwing the heck out of the ball and doing a great job, it enhances [the rotation] even more," he said.
David Furones is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.