A poor bowler is called a 'pie-thrower' or a 'pie-chucker'. Does anyone know why this is so; particularly, why 'pie' was adopted for this phrase when it could have been just about anything?
This is just a guess, because I don't see any specific mention of "pie thrower" in the OED or any of my other big dictionaries, but my Webster's Third New International Dictionary (Unabridged) lists one of the meanings as: "something easy or much desired" (as in "it was easy as pie"). Perhaps that is part of it, as in bowling something that is slow and easy to hit. Also, if you think about how a pie is thrown, you realize it doesn't go very fast and it is big and fat and round ... not something a competent batsman would miss, I should think.
Clowns in the circus throw pies; they do not bowl them as the bowler in cricket must (mostly 'arm straight', for the benefit of those not brought up in the noble art of cricket). So do unruly diners in a food fight. The bad bowler is being compared to such undisciplined behaviour - and it is not complementary. The implication is that anyone could do what they're doing...and about as badly.
As to why a pie rather than anything else - not sure, but likely because the result of throwing a pie is a mess, whereas throwing other things might, or might not, be as messy.
It's not known exactly, but the phrase originates with Rod Marsh, the former Aussie wicket keeper in 1993. Australia had repeatedly hammered England's medium pacers and Marsh came up with this disparaging phrase to describe their ineptitude. Presumably clowns are what he had in mind, although he was never pushed for a definition. Speaks for itself.