Wheeler was drafted by the Colorado Rockies in the first round, 32nd overall, of the 2009 Major League Baseball Draft. He made his professional debut with the Tri-City Dust Devils, playing in 68 games and hitting .256 with 5 home runs and 35 RBI. Prior to the 2010 season, he was ranked as the Rockies' seventh best prospect by Baseball America. Wheeler spent the 2010 season with the High-A Modesto Nuts, playing in 129 games and hitting .249/.341/.384 with 12 home runs, 63 RBI, and 22 stolen bases.
