The 28-year-old midfield schemer said: "I was very disappointed not to start, to be honest. I didn't find out until before the game so I had no idea.
"I was surprised and disappointed at the same time, but it's one of those things.
"I had no inkling what the team was going to be and it's a bit of a mystery to me. Maybe the manager will pull me aside to explain."
Royals boss Steve Coppell stated: "John has said nothing to me about it. My door is always open but he's mentioned nothing so far. Now he's a concern this weekend."