Santana will serve as the Mariners' designated hitter and cleanup batter in Wednesday's game against the Padres.
Santana will be making his fifth consecutive start after going 3-for-14 with a pair of home runs and three RBI over the previous four contests. While Mitch Haniger (back) is day-to-day, the Mariners look as though they'll have regular spots in the lineup available for both Santana and corner outfielder Sam Haggerty.