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: Jason Hammel will make his second spring start on Tuesday when the Cubs face the Rangers in a 9:05 p.m. CT game in Surprise. Hammel's first start was delayed because of rain, and he also has pitched in a "B" game. In the right-hander's last outing, he threw 75 pitches over six innings. Top prospect Javier Baez is expected to make his second start at second base as well. The game will be available via a exclusive cubs.com audio webcast and on MLB.TV
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.