Billy Sharp was attacked in the wake of the play-off semi-final defeat atNottingham Forest.
The Blades fought back from a two-goal deficit to level the tie at 3-3 on aggregate and force extra-time and penalties at the City Ground but their spirited fightback was snuffed out in the penalty shoot-out.
There was jubilation at the prospect of ending their 23 year absence from the premier league, but it was overshadowed by an unprovoked attack on Sharp.
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Sharp, who was injured and did not play in the second leg of the play-off semi-final, watched on from the touchline as the Forest supporters celebrated their 3-2 penalty shootout victory.
Sharp is said to have required stitches after the attack.
He said that he watches every Monday Night Football, every Super Sunday, and his time up in Scotland, and that many people talk about seeing things thrown on the pitch, fans invading the pitch, and things that put players' health and safety in danger. Nothing has ever been done about it. Something will be done about this.
We have seen it. We know what happened. There is a prison sentence there. How can you come to your place of work, minding your own business, and get attacked? It is bang out of order. We hear people condemn it and nothing is done about it. We are the ones who suffer. It is upsetting for a lot of reasons.
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The attack on Sharp, who played for the club on loan during the 2012/13 season, was denounced by the club and they vowed to ban his attacker for life.
Billy Sharp, a former player for the club, was attacked after the match at The City Ground.
The club will work with the authorities to locate the individual in order to hold them to account for their actions, which will include a life ban from the forest.
The Club would like to apologize to Billy personally.
Michael was a pundit for Sky Sports at the City Ground and expressed his disbelief at the attack on Sharp.
He said that Billy Sharp was standing there doing nothing wrong and that too many people run on the pitch. One stupid fan spoilt everything when he ran on. I hope Sharp is doing well.
It happens every year at the end of a season when one team has disappointment and another team has joy, I worry for the opposition when fans run on. It only takes one situation for someone to be seriously injured.
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Michael Brown, a former player for the United Kingdom, said it was absolutely ridiculous.
It does worry me when fans run on. It ruins it a bit. Fans want to go on, but idiots can ruin it.
It has to be punished. Fans will have to stop running on special occasions. The person needs to be punished.
When will this stop? When are people going to realize that this is not acceptable?