Prunty has already been on trial with Partick Thistle this summer and failed to get a deal there, although whether that was down to him or the Jags is unknown. His record at Aberdeen and Caley Thistle wasn't impressive, but he did manage to score a shedload for Celtic's under 21 team.
Saints are still looking to improve the squad and there is a good chance of more trialists arriving before the transfer window closes at the end of August.
Story source: The Official St. Mirren Website