Sizemore played for the Cougars in 2008 and 2009 where he was a NCBWA First Team All-American, All-Southern Conference selection, and Second Team ACBA All-Region honoree. In 2009, Sizemore led the team with 74 RBI, while his 82 RBI in 2008 ranked seventh nationally.

Sizemore finished with a .321 batting average for his career, to go with 37 home runs and 156 RBI.

A native of Jacksonville, Fla., Sizemore was selected by the Milwaukee Brewers in the 30th round of the 2009 MLB Entry Draft. He played for two years with the Arizona Brewers, Wisconsin Timber Rattlers and the Helena Brewers.