But he revealed that he came very close to a move to Stoke, as he did not feel a bigger team would come through with an offer.
Robertson said on Open Goal: "Stoke were quite interested in me.
"Mark Hughes liked me and I think there was a wee bit of chat with them.
"So I was thinking they were a really good option.
"I think they finished top ten that season and I was trying to get my head on [a move to] Stoke.
"I wasn't sure if I was going in as backup to him as he was flying that season."