In 1990-91 Sleep was dropped from South Australia after taking only four wickets at an average of 98. He was back in the team in December 1991 after some strong performances at domestic level. South Australian coach Peter Philpott said ""Peter's future Shield career will now depend on whether he's good enough to bowl leg-spinners at this level and get results. It will be dependent on that, not on his batting. If he can't do it we'll have to look elsewhere."