This latest setback means the club will make the journey north without five recognised first team players, with Jason Holt - though he is back training - and Jamie Walker still out injured and Kevin McHattie and Callum Paterson unavailable through suspension.
Smith was forced off at half-time with a knee injury during the recent League Cup semi-final defeat to Inverness Caledonian Thistle and was sent for a scan earlier this week after the problem flared up in training. "It's a massive blow for the lad as I thought he had being doing fantastic for us recently," said Locke.
"The problem flared up and we sent him for a scan. [But] he doesn't require surgery and just has to rest then things should settle down."