Diamondbacks send Madison Bumgarner back to Arizona for tests on arm

LOS ANGELES — The Diamondbacks sent left-hander Madison Bumgarner back to Arizona to undergo testing on his left arm after he said he experienced “arm fatigue” during his start against the Los Angeles Dodgers on Saturday night, manager Torey Lovullo said. “We just thought it would be the best thing for him to get back to Phoenix to let our doctors get a look at him,” Lovullo said. “On the urgency scale, I don’t think it’s very high, but it’s all precautionary at this point.” Bumgarner’s fastball velocity was down more than 2 mph early in Saturday’s start, prompting Diamondbacks…