Grubb fell two games short of qualifying for the 2006 World Matchplay, losing to Andy Hamilton who eventually qualified. He then fell one game short of qualifying for the 2007 PDC World Darts Championship. Having beaten Tom Kirby and Paul Williams, he lost in the final game to Wayne Atwood. In 2008, Grubb secured his best ever performance in the PDC Pro Tour, reaching the last 16 in the Players Championship in Las Vegas, beating David Fatum and Tony Ayres before losing to Mark Frost. Then reached the 1/4's in a pro tour event in Scotland losing a narrow game to Michael Van Gerwen.