Naps: How Many and How Often?

I have a 12 month old son and I'm wondering if I need to cut out one of his naps. He wakes up @ 7:30 or 7:40 like clockwork, he goes down for his first nap @ 11:00 (until 12:30 -12:45) without a boo and then again @ 4:00 (until 5:15) and is in bed by 8:30 - 9:00 @ the latest. Lately he's been waking up @ around 6:00 - 6:30, he still takes a nap @ 11 without a problem but @ 4:00 most days he does not want to nap, instead he'll play in his crib and eventually fall asleep but he plays for some time (45 minutes or longer). His night time sleep is no longer very good, he wakes often and is up as I said much earlier than usual in the morning. I'm wondering if maybe I should try pushing back his morning nap alittle and cutting out his afternoon nap completely but everything I read says that babies usually give up the morning nap but that doesn't seem to be the case for my son. Maybe I'm completely off the mark and it's something completely different causing these problems, any ideas?