Bumgarner, one of the best-hitting pitchers of his generation, became the first starting pitcher intentionally allowed to bat at an AL ballpark since Ken Brett for the White Sox in 1976 — and he started the Giants’ biggest inning with a rocket of a leadoff double in the third. The Giants scored six times in the inning, then added two more in the fourth against left-hander Dillon Overton in a 12-6 victory over the A’s at the Coliseum, avoiding a four-game sweep. Tampa Bay’s Andy Sonnanstine had to bat for himself in a game in 2009 because of a lineup card mixup, and Billy Martin had pitcher Rick Rhoden DH in a game in 1988, but Rhoden was not the starting pitcher. The first two pitches I threw to him I thought were strikes and the umpire didn’t really help me out with those, which led me to having to put one in the zone so he could call it a strike. [...] came the back-to-back homers: a three-run shot by Buster Posey and a solo shot by Brandon Crawford. A’s reliever Fernando Rodriguez walked in two runs in the ninth, and Marc Rzepczynski gave up a two-run single by Belt. Crisp hit a two-run double in the bottom of the inning. The A’s earlier runs came on a solo homer by Marcus Semien in the first, his 16th of the year; an RBI single by Jake Smolinski in the fourth; and a two-run homer by Yonder Alonso in the seventh, his second in two nights.