Sosa will start at shortstop and bat eighth in Monday's game against the Cardinals.
Sosa will pick up his first start in a week, stepping into a spot in the middle infield in place of a resting Trea Turner. The 30-year-old has seen most of his opportunities against left-handed pitching this season, but he'll draw a rare start against a righty (Hunter Dobbins) in the series opener in St. Louis.