Pitching in front of a reshuffled lineup, the 22-year-old gave up two hits and struck out six over six innings, but a James Loney single lifted the Rays to a 1-0 over the Royals on Tuesday.
Kansas City (3-4) was without Omar Infante, who suffered a laceration and a sprained jaw after being struck by a Heath Bell fastball on Monday. That bumped Eric Hosmer to the two-hole and placed Danny Valencia into the order.
The bats failed to match Ventura's productivity, going 9 for 34 while stranding 10 runners.
Mike Moustakas recorded his first hit of the season to start the ninth after cutting off an infield grounder by Wil Myers to Alcides Escobar. Moustakas couldn't get the ball out of his glove, and Myers ended up as the go-ahead run on Loney's RBI off Greg Holland.
It was the only hit of the night for Myers, who struck out three times against Ventura.