[TWEET]https://twitter.com/JaymOU13/status/1485012814460768258?s=20[/TWEET]
I found a tweet that had the actual replay of the hit. At the bare minimum this should have been a common foul, and there is enough justification for a flagrant foul 1.
From the video, Mayer jumps to block Grove's is shot, but he's jumping recklessly.
This clip from youtube has the full play -
https://youtu.be/gne5Lnhv9ew?t=869.
Goldwire throws an inaccurate pass, which causes Groves to not catch it cleanly, and he has to bend/turn to gather the ball. As soon as Mayer saw the pass, he crashed in to help, and pre-determined he was going for the block.
If Groves catches it cleanly, it's still a foul cause Mayer was jumping in no man's land. In this scenario, Grove's feels him, and just holds on to the ball to draw the foul.
It's at least a common foul because he's jumping into Groves. Enough justification for a flagrant 1 cause a knee to the head is excessive.