Prior to that, Chen retired 10 straight batters. Chen gave up two runs - both on homers - in 6 1-3 innings.
Milone allowed three runs and eight hits in six innings.
Donaldson put the A’s up 1-0 in the first with his 17th home run, and Norris connected leading off the second.
Baltimore used three straight two-out singles, the last by rookie Jonathan Schoop, to get a run back in the bottom of the second.
Chris Davis tied it in the fourth with an opposite-field drive to left, and Machado homered in the fifth for a 3-2 lead.
NOTES: The Orioles put RHP Miguel Gonzalez (strained right oblique) on the 15-day DL, recalled RHP Tim Berry from Double-A Bowie, purchased the contract of Meek from Triple-A Norfolk and optioned RHP Preston Guilmet to the same club. … Kevin Gausman replaced Gonzalez as Baltimore’s starter vs. Oakland on Saturday. The A’s will call upon right-hander Sonny Gray (6-1, 2.45 ERA). … Former Orioles closer Jim Johnson returned to Baltimore for the first time since being traded during the offseason. “A lot of memories. It’s obviously different going into a different clubhouse. It’s cool,” Johnson said. … Oakland has homered in 14 straight games. … LHP Johan Santana, who hoped to make a comeback with the Orioles, tore his Achilles tendon in extended spring training and is lost for the year.