A.C.
Perhaps he wants to nap more, but is conditioned that you will go in and get him if he stirs. When my daughter was younger, I encountered a similar problem. I found that when I thought she was awake or waking up that she was in fact either just adjusting or getting ready to fall into a deeper sleep and I kept going in and getting her up because I thought she was awake. Perhaps you should wait 10 minutes or so before going in to see if he goes back to sleep. Believe me he wants to nap.