Asleep!

This happened a week or two ago. Lucas didn't take a nap during the day and as I was holding him later that day he kept falling asleep, and I would gently shake him awake. I set him on the floor to play and I looked over and there he is curled up with his knees under him on the kitchen floor trying to sleep. It was about 5 o'clock and I did not want him sleeping, so I turned on some tv and gave him his sippy cup, thinking that will deter him trying to sleep. I started making dinner, and realized that he had been really quiet, and that is when I found him curled up with his knees under him, sippy cup in hand, asleep on the floor in front of the tv. I don't know how long he was there, it couldn't have been more than 30 minutes. If you know my child at all, you know this is not like him at all. He doesn't fall asleep till I set him in his crib at night, during nap time, and occasionally in the car, but he doesn't just randomly plot himself on the floor and try to voluntarily go to sleep.