Cubs right-hander Rich Harden, who has been on the disabled list since May 18 with a mid-back strain, tossed 4 1/3 innings in a rehab start for Triple-A Iowa on Monday.
Harden allowed two runs, one earned, on three hits against the Round Rock Express while striking out six and walking two.
He was removed in the fifth inning after throwing 70 pitches, 44 for strikes.
Harden suffered from flu-like symptoms over the weekend but felt better on Monday and made his first rehab start for Iowa.
The 27-year-old is 4-2 with a 4.74 ERA in eight starts with the Cubs this season.
He could return to the club as early as Saturday against the Twins.
Rhett Bollinger is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.