Watkins (0-1) took the loss Tuesday, allowing five runs on seven hits and two walks over 4.1 innings against the Cardinals. He struck out four.
The 30-year-old righty put Oakland in an early hole during his season debut, giving up a two-run homer to Nolan Arenado and a solo shot to Jordan Walker in a four-run first inning. Watkins started 30 games for Baltimore over the previous two seasons, posting a record of 7-13 with a 5.85 ERA and 1.51 WHIP across 160 innings during that span. If he sticks in the rotation, Watkins tentatively lines up to face the Royals at home early next week.