The Blades captain was sidelined for the second leg because of injury prior to the incident.
Daniel Sturridge fired the Reds ahead on 35 minutes in Basle but the Spanish side rallied to secure a third successive triumph in the competition.
Nottingham Forest are just a game away from a return to the Premier League after they won a dramatic penalty shootout against Sheffield United to reach the Championship play-off final. Forest looked to be in a commanding position after the first leg when they came away from Bramell Lane with a 2-1 win, and the constantly impressive Brennan Johnson extended that lead in the first half at the City Ground. Sheffield United were much improved from their first leg performance, though, and they were able to level the tie through Morgan Gibbs-White and John Fleck.