The Republic of Ireland Under-21 international has missed the last four matches after badly fracturing his finger during last month's 3-0 defeat at Brentford but has had the protective cast removed and could be included.
Town, assured of a play-off place, have an outside mathematical chance of snatching automatic promotion but must win and hope for a highly unlikely sequence of other results.
Clark has no other new injury or suspension problems and faces a selection dilemma up front.
Lee Novak pressed his claims for a return to the starting line-up with the late winner after stepping off the substitutes bench last week while Robbie Simpson is fit-again following a long-term thigh injury.
Leading goalscorer Jordan Rhodes, who has netted 23 times this season, and 16-goal Theo Robinson started against Colchester last week.