David Mark Eckstein (born January 20, 1975 in Sanford, Florida), nicknamed "X Factor," is a Major League Baseball infielder for the San Diego Padres. He is noted for his size, as he is small for a professional sports player at 5' 7". Eckstein's name is pronounced (ECK-styne) and means "cornerstone" in German. His "walkup music" is Ludacris's "Number One Spot" (appropriate since Eckstein usually bats as the leadoff hitter) and Crystal Method's "Busy Child."

Eckstein played baseball all four years at Seminole High School in Sanford, Florida. He was a two-time All-State athletic selection, and a prominent member of a state championship team.

He was also a member of the National Honor Society and the Fellowship of Christian Athletes. David was voted "Most Helpful," in the Class of 1993.