"There's no hard and fast rule in appointing managers nowadays. You see some managers go in who have little experience - Diego Simeone, Pep Guardiola or Kenny Dalglish all those years ago. Then there's the idea of managers who have one or two good seasons like Jose Mourinho. It worked for Chelsea and then Andre Villas-Boas didn't. You've seen different examples of how sometimes it works and sometimes it doesn't work. There is no hard and fast rule and until you appoint someone you haven't got a clue whether it's going to work or not. From that point of view, people say Ryan's got no experience but then is Van Gaal going to work? We don't know. It's a call for people at the club."