Speaking to the Monday editition of the Nottingham Evening Post, Hamshaw said "It should not have been a sending off, it's as simple as that - and that makes it so frustrating.
"It was a booking in the first half but no-way was it in the second half because I didn't even touch him.
"People know that I am an honest lad and if you know you deserve to go then you can accept it.
"But I think in this case their left-back has got me sent off.
"From a professional point of view it was good for them, but not from a sportsmanship point of view. It has cost us two points and I feel a bit responsible because I was the player involved."