That's what Roger Waters said. However, Nick Mason's take on it is different. There's a difference between being able to nail something straight away (as a top session player such as Andy Newmark or Jeff Porcaro do day in day out) and taking weeks to work something out as might have been required for Nick to do it. See, e.g., http://floydlyrics.blogspot.com/2010/03 ... unset.html There is a difference between being utterly incapable of doing something, and it taking a long time to achieve that something.
Remember that all Floyd members have had others play their parts. Bob Ezrin played plenty of keyboards on The Wall. Dave Gilmour played lots of bass instead of Roger. (And Roy Harper sang a Rog song). Joe DiBlasi played guitar on 'Is There Anybody Out There' instead of Dave. There are other guitarists and keyboardists on TDB, etc. But, people only seem to talk about when Nick was replaced on a song.