You keep saying that but I don't see you adding a reference. You are going to need to add a reliable source to back that up. I don't think he was anything other than a touring member since they already had a keyboard player and there's little point in having two. Find a source and it can go in, but it doesn't go in the timeline or in the infobox, or the template. There have been dozens of touring members and session guys with Fleetwood Mac.