Mercado signed a minor-league contract with the Padres on Dec. 28.
Mercado played in 20 big-league games with the Cardinals last season, racking up nine hits and five RBI in 32 trips to the plate. Down in Triple-A, he slashed .298/.366/.521 with 14 homers and 62 RBI between three different organizations. The Padres have limited outfield depth on their current big-league roster, so Mercado may have a decent chance of playing in San Diego this season as a bench piece.