They say the last order bell has been sounding unmanned and believe Mr Harris, a popular customer of 30 years who recently passed away, is haunting them.
Barmaid Tasmyn Burns, 19, was serving pints when the bell rang out on a Sunday afternoon.
She said: 'It made us all jump because it was ringing so loud. It was really being yanked with some force.
'I thought someone may have been playing a joke or something so I was shocked when I saw no one else was there.
'I don't normally believe in ghosts but it's quite hard not to after what happened. I have heard a few whispers of peoples saying it could be the spirit of Nigel.
'He was always in the bar and he did everything with the club, his picture is even hanging up in the lounge'.
Bosses had planned to bestow an honorary lifetime membership on him but he died before they could do it.
Manager Frank Bright said: 'A few people have mentioned Nigel's name. He was great man, an all-round good guy - and certainly no threat to anyone.'
'The bell ringing on its own is pretty odd, I'll give you that,' he said. 'And one of the girls was quite freaked out.
'But I'm a bit more level-headed and I'm sure there's some way to explain it; I just can't put my finger on it at the moment.
'There was one time I was here on my own and I heard a whistle. I turned round and shouted "hello, hello" but there was no-one here.
'You hear voices every now and then but it could just be someone outside. The walls are made of wood but pretty thin.
'Maybe we could use it to our benefit - £25 a night to stay in the haunted bar, how does that sound?'
The rugby club's events manager Sue Stone added: 'I've seen the video and it looks pretty genuine but I'm no expert on these things.
'I know the bar staff have said they've heard things in the past and it's certainly strange.'
Source: Daily Mail UK