Fernando Tatis Sr. is a former professional baseball player from the Dominican Republic. He played in Major League Baseball (MLB) primarily as a shortstop and third baseman during the late 1990s and early 2000s. Tatis is best known for his time with the St. Louis Cardinals and the Montreal Expos. One of Tatis's most notable achievements is being the only player in MLB history to hit two grand slams in a single inning, which he accomplished in 1999. He is also the father of current MLB player Fernando Tatis Jr., who plays for the San Diego Padres.