Sleep training

I decided I will sleep train my 7 month old, but he already tries to stand on his crib. I’ve lowered it so not concerned on him falling, but because he still doesn’t have the strength to stand up the way he gets in position sometimes has his feet or legs sticking out of the crib, and I’m worried that if he fell cus he lost balance if his feet are in there he could hurt himself badly break it or something so I’m not sure what to do with that because I need to sleep train him