This looked really bad -- perhaps even malicious -- when it happened in real time. Luckily, it seems as though it's neither.
Grossmann stayed down for a while, but eventually got up under his own power. He went right to the dressing room rather gingerly, but quickly returned to the bench. He appears to be OK, which is obviously a good thing given the current state of the Flyers defense.
Kesler didn't do anything wrong here. It was just an unfortunate play where Kesler's left skate accidentally clipped the back of Grossmann's left skate, and Grossmann just couldn't stop himself. Luckily everything appears to be alright.