Underwood was recalled from Triple-A Iowa on Monday, Jesse Rogers of ESPN.com reports.
Craig Kimbrel (knee) was sent to the injured list in a corresponding move, allowing Underwood to rejoin the Cubs just five days after his most recent demotion to the minors. Underwood has yet to log an appearance in the majors this season; he owns a 5.09 ERA, 1.53 WHIP and 86:38 K:BB in 76 innings at Triple-A.