First of all, diving to save a ball is not blocking the ball (at least to me). It is more like forcefully throwing yourself onto the ground, with the side effect of possibly changing the balls direction of movement.
Now, you might think this might not be so bad. “I once fell and it didn’t really hurt Ethan! You can’t be complaining about something like this!” Well let me tell you. If you ever wind up in Goalie practice and you hear coach say: “All right everybody! This weeks focus is on diving!”…
Your hip bones will never be prepared for the traumatizing experience that lies just ahead.
Dive after dive, whistle after whistle, “ouch!” after “OUCH!!”, again and again and again. The turf burns like a match you forgot to blow out, and then landed on you toe. It burns like brake pads coming into the hairpin at Canada (for all my F1 peeps out there). It BURNS like the suns core, slowly biting away at you skin. It’s not quite the movement that hurts, it’s the repetition that slowly forms the impeding bruise on your side.
With this evidence, along with experience, I thing this might, just might, hurt.