I think there was no intention, but he went directly on his wrist with an open foot . If it was more harsh he would have broken his wrist.
Zambrotta probably didn't have an intention to hurt him (actually he didn't. Marek was faster and since Zambrotta missed the ball he caught his wrist) but he wasn't careful at all and with a little more power in that start Hamsik's career would have been threatened.
Of course, the ref doesn't give a yellow.
Listen, i know you don't want to hear about a fixed scudetto and you want to enjoy the league till the end, so sorry for my posts, but i can't help saying it as i saw it and i can't help being mad at the help Milan are getting from the refs this season.