Board Thread:Naruto Discussions/@comment-4670387-20161010075427/@comment-25632268-20161010144519

Samurais were perfectly capable of using chakra, while Gai and Lee weren't (with exception of opening inner gates, but I don't think it really counts as even the auras around them were not chakra). So yeah, there would be no problem for samurai to perform ninjutsu.