McDonald, a free agent who signed with the Cubs in February, is competing for the fifth spot in the rotation. He was bothered by shoulder issues last year while pitching for the Pirates.
Right-hander Yao-Lin Wang relieved McDonald and gave up a pair of runs on two hits and a walk with one strikeout.
Brandon Moss led off the second inning with a hit and, after advancing to second on Stephen Vogt's walk, came around to score on Nick Punto's single. Vogt scored on Eric Sogard's ensuing sacrifice bunt.
Moss struck again in the sixth with an RBI double, plating Yoenis Cespedes, who snapped an 0-for-23 skid with a single. Moss, who is hitting .464 (13-for-28) this spring, then came around to score on another hit from Punto.
Savery, competing for a bullpen spot, pitched two shutout innings for the A's. Another left-handed bullpen candidate, Fernando Abad, also tossed a scoreless frame, as did Sean Doolittle and Jim Johnson. Zach Neal fanned four over two innings.
Jonathan Mota hit a two-run homer for the Cubs in the ninth, and outfielder Ryan Kalish had two hits.
Up next: Right-hander Jesse Chavez, suddenly expected to start the season in the A's rotation in the midst of injuries to Jarrod Parker and A.J. Griffin, will be on the mound Tuesday for a 1:05 p.m. PT start (live on MLB.TV and an exclusive athletics.com audio webcast) against the host White Sox at Camelback Ranch in Glendale, Ariz. Chavez has been lights-out for the A's this year with 12 2/3 scoreless innings.
Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.