I'm having trouble understanding this sentence from a soccer manga I like to read. There is not much context to the sentence, and further, the character often uses slang.
The whole sentence is this:
まああんなのは棚からなんとやらだ.
It is said by a player who is about to kick a ball. People in the stands are cheering him because he's really good at kicking from far away, and he's somewhat irritated that they put pressure on him.
Someone suggested to me that it might be related to "棚から牡丹餅" but it doesn't seem to me to make sense.