Mize will start Wednesday's game against the Diamondbacks in Arizona.
After acquiring Mize from the Tigers on Monday in a four-player deal, the Padres will waste little time breaking the right-hander into the rotation. Mize had been enjoying a career-best season with Detroit, posting a 2.70 ERA, 0.99 WHIP and 85:19 K:BB while limiting opposing hitters to a .213 average over 86.2 innings.