Of the dozen leap day babies in major league history, only one has played for the Padres. Outfielder Terrence Long spent the 2004 season with the Friars as Bruce Bochy's fourth outfielder and go-to pinch-hitter. He was acquired a few months before his seventh birthday along with Ramon Hernandez in the trade that sent Mark Kotsay to Oakland. He adapted well to his first part-time role, posting career highs with a .295 batting average and OPS+ of 103, and was considered starting material by Kansas City, who sent Kevin Towers starting pitcher Darrel May and reliever Ryan Bukvich for Long and former prospect Dennis Tankersley, who never saw time in the bigs again.
Long was merely adequate for the Royals in 2005, and wrapped up his career with twelve games for the 2006 Yankees, retiring well before his eighth birthday. According to his rarely-updated Twitter account, Long remains an A's fan and has a youth baseball academy.
Welcome to double-digits; you're officially a tween!