Baseball-card stats refer to the statistics that are printed on the back of baseball cards. These stats include ERAS (Earned Run Average), HRS (Home Runs) and RBIS (Runs Batted In). ERA is a statistic used to measure the number of earned runs a pitcher gives up per nine innings pitched. Home Runs is a statistic that measures the number of times a batter has hit a home run in a season. RBIs is a statistic that measures the number of runs a batter has driven in during a season.