Greg started his career with Philadelphia from 2004–2005, but only played one game. The next year he was acquired First Round, First Draft Pick in the supplemental draft in 2006 by the Los Angeles Riptide. He was chosen above 223 others. He played 12 games in 2006 and scooped up 27 ground balls. In 2007 he had 3 points and 39 ground balls, was selected as an MLL All Star, and was chosen as the New Balance Sportsman of the Year. Greg continued his phenomenal play for LA in 2008 and served as captain while netting 3 pts and picking up 35 ground balls.