PHOENIX — Minutes before Monday’s trade deadline, the San Diego Padres struck a deal with the Detroit Tigers to acquire a rental pitcher they believe can front a postseason rotation. Casey Mize, in an ideal scenario, will make only 10 or so regular-season starts for his new team, then at least a few more before earning generational wealth in free agency.Wednesday presented Mize with an immediate opportunity to pitch the Padres into playoff position. Instead, in a 10-4 loss to the Arizona Diamondbacks, the right-hander recorded 10 outs, allowed a season-high nine hits and surrendered a career-worst eight runs.“Not the first impression I wanted to make for my teammates and for the fans,” Mize said. “Pretty tough time to have the worst start of my career. Kind of just put us in a really tough spot and didn’t give us a chance to win, so frustrated and embarrassed by that.”Which MLB teams did the most?Levi Weaver and Madison EadesNo pitcher had given up eight or more runs in his Padres debut since the Los Angeles Dodgers bombarded Jhoulys Chacín for nine on Opening Day 2017, when San Diego was in the midst of a rebuild. Mize, pitching with far higher expectations, lacked his characteristic command. The three walks he issued matched another season high.He paid for his lack of precision in the third, when a leadoff walk came around to score and Tim Tawa drilled a two-out home run. In the fourth, everything unraveled. The Diamondbacks strung together five consecutive hits and a bases-loaded walk before Padres manager Craig Stammen went to the mound. All three inherited runners scored off lefty Kyle Hart, though the damage was charged to Mize.