Arizona Diamondbacks right-hander Zac Gallen's 2026 looked, at first, like it might have been a corner-turning season. But the early-season optimism is quickly evaporating with each passing start. That continued in a notable fashion on Tuesday night, as Gallen was knocked around by the Texas Rangers at Globe Life Field . Gallen was charged with seven earned runs (including two homers) over the course of just 4.2 innings. Granted, there were some defensive miscues behind him. But it was a continuation of several trends that are simply becoming impossible to ignore . The truth is, Gallen simply isn't the arm he once was. That's not to say Gallen cannot return to a certain level of dominance, or even consistent solidity. But after a career-worst season in 2025, Gallen's results and underlying metrics are telling a similar story of decline thus far this season. In fact, they're getting worse.…