Smith had been farmed out to the First Division side in December, but his own stay was cut short by a broken foot after three appearances.
The 24-year-old has failed to regain his place after picking up a serious knee injury in March 2009.
St Mirren have since signed Paul Gallacher and Mark Howard, with Smith finding himself third choice behind that pair with the Scottish Premier League outfit.
Paterson, who had displaced on-loan Oldham goalkeeper Greg Fleming in Dunfermline's startling line-up, was injured in the 2-1 victory over Dundee following a tackle by on-loan Celtic striker Ben Hutchinson.
Dunfermline manager Jim McIntyre, whose side remain in the race for the Division One title and promotion along with Tuesday's opponents, said he thought there had been no malice in the challenge.
Source: BBC Sport
Source: BBC Sport