Velasquez (3-7) suffered the loss against St. Louis on Friday, allowing four runs on four hits and no walks while striking out four over four innings.
The veteran hurler was called up to the big club earlier Friday after signing with San Diego on Wednesday. He gave up three runs -- including two on a Tyler O'Neill home run -- in his first inning of work and served up a solo shot to Dylan Carlson in the fourth. There was some rust to be expected as Velasquez's start was his first in the majors since July 30, but it was nonetheless a disappointing debut given San Diego's slipping grasp on a playoff spot. Velasquez figures to get another start with Blake Snell (groin) currently on the injured list, and he's lined up to face San Francisco at home next week.