A win for United would give Jose Mourinho's his fourth League Cup trophy, tieing him with Brian Clough and Alex Ferguson for most won as manager.
He will have to make do without in-form attacker Henrikh Mkhitaryan after he was injured in their Europa League tie mid-week.
Tipperary's Shane Long is in contention to feature for the Saints the Gorthanoe man's semi-final goal against Liverpool ensured their place in the final.
