The Padres selected Harris' contract from Triple-A El Paso on Monday.
Harris inked a minor-league contract with the Padres before the All-Star break after being granted his release from the White Sox in early July. He has a 1.039 OPS with 10 steals, six homers and 26 RBI over 135 plate appearances with El Paso this season, and the move bolsters a Padres outfield that is without Ramon Laureano (hip), Samad Taylor (oblique) and Miguel Andujar (wrist). In corresponding moves, Sung-Mun Song was optioned to Triple-A and Lucas Giolito (elbow) was transferred to the 60-day injured list.