Nottingham Forest have said they are “appalled” after the Sheffield United striker Billy Sharp was “assaulted” by a fan during the post-match celebrations after their side won in the Championship play-off semi final. The fan, a man dressed in a yellow top and blue trousers, is seen in television pictures headbutting Sharp, who was on loan at Forest from Southampton during the 2012-13 season, as he watches the celebrations from the touchline. As Sharp lays on the floor, the man sprints away from the scene. The Sheffield United manager Paul Heckingbottom told Sky Sports: “There’s a prison sentence there for sure. We’re seeing things thrown on the pitch and things that are thrown on putting players’ health and safety in danger and nothing’s ever done about it. There will be something done about that. We’ve seen what’s happened, we know what’s happened. “How can you come to a place of work minding your own business and be assaulted in that fashion? It’s just bang out of order and it’s everything that’s wrong. Too many times we hear people condemn it, but nothing’s done about it. We’re the ones that suffered. “It’s assault. We’ve seen one of our players attacked. He’s shuck up, bleeding, angry. It’ll be dealt with. “It’s upsetting for a lot of reasons - I don’t want to say too much more about it. He’ll be dealt with.” ”Nottingham Forest Football Club are appalled to learn that our former player, Billy Sharp, was assaulted leaving the pitch after tonight’s match at The City Ground,” the statement read. “The club will work with the authorities to locate the individual in order they are held to account for their actions, which will include a life ban from Nottingham Forest. The club would also like to apologise to Billy personally and to Sheffield United.” Nottingham Forest lost the game 2-1 on the night, but a 3-3 aggregate score meant the tie was settled by a penalty shootout, which was won by Steve Cooper’s side 3-2. They will now go to Wembley to face Huddersfield for a place in next season’s Premier League on Sunday 29 May.