Contreras registered a no-decision during Sunday's 4-2 loss to San Diego, allowing two runs on five hits and one walk with three strikeouts in five innings.
Contreras was able to escape a bases-loaded jam in the second inning but served up a Jurickson Profar two-run shot with two-out in the fifth to fall behind. The 22-year-old has impressed in two starts since returning from the minors, compiling a line of two earned runs on eight hits and three walks with eight strikeouts in 10 innings. If he sticks in the rotation, Contreras will likely take the mound against Arizona next weekend.