S.L.
I would introduce the idea. Make it fun. I'm sure you've heard of putting cereal in the toilet and he aim at it. Just remember that sometimes if they are trained early, they will relapse.
Also, another thing is that he may just be taking his diaper off because he doesn't want it on. My daughter did this. It wasn't that she was ready to train, it was because she didn't like the diaper. We switched to a less bulky diaper and just put them on backwards. Of course I was fussed at by some people for stiffling her desire to go potty, but she wasn't interested. If I put her on the potty, she would scream her head off.
If he is interested, go for it. Good Luck!