This autographed jersey has been personally hand-signed by Sammy Sosa of the Chicago Cubs. This autograph is certified by James Spence Authentication (JSA). It comes with the numbered hologram and matching Certificate of Authenticity. Samuel Kelvin Peralta Sosa (born November 12, 1968) is a Dominican American former professional baseball right fielder. Starting his career with the Texas Rangers, Sosa became a member of the Chicago Cubs in 1992 and became one of the game's best hitters.