Salas will start at catcher and bat sixth in his major-league debut Wednesday in Cincinnati.
Salas was among the Padres' September call-ups Tuesday and is set for his first start in the big leagues during Wednesday's series finale. The 20-year-old catcher has slashed .296/.374/.448 with 10 home runs, 17 stolen bases and a 47:58 BB:K over 96 games between Double-A San Antonio and Triple-A El Paso this season. Salas is likely to see the bulk of the starts at catcher down the stretch for the Padres.