[AZ Central] Diamondbacks’ Zac Gallen set to return from injured list; Christian Walker now out - Diamondbacks right-hander Zac Gallen will be making his return from the injured list on Tuesday, but based on the way he felt, he might have never needed it in the first place. Gallen said the first few days after he was told in late March that he had a hairline fracture in his right forearm were the best his arm had felt all spring training. He understood the reasoning for holding off and letting time run its course, but he couldn’t help but feel frustrated.