I've never thought about it before so I've just asked a mate who has worked at a few football clubs and will have seen the contract of every player when at all of the clubs and been told that some do get it but it depends entirely on their contracts.I have heard of appearance bonuses. I have never heard of being named to the bench bonus. It’s not a thing.
With that in mind, I expect it is something that ortga negotiated into his contract seeing as he was brought in specifically to be the sub keeper.
I doubt city aren't putting him on the bench in cup games to save a couple of grand though.
