Greinke was born in Orlando, Florida. After being named the Gatorade National Player of the Year in 2002, he was selected out of Apopka High School (and turning down a scholarship to Clemson) in the first round of the 2002 draft. In 2003, he played for the Wilmington Blue Rocks and Wichita Wranglers, where he was named the Royals Minor League Pitcher of the Year, Carolina League Pitcher of the Year, and The Sporting News Minor League Player of the Year, with a 15–4 record and 1.93 ERA.