Willie Mitchell's been there.
The Florida Panthers captain and outspoken NHLPA member took to social media on Wednesday in support of Dennis Wideman, the Calgary Flames defenseman who was handed a 20-game ban for cross-checking linesman Don Henderson.
The NHL confirmed that Wideman, though failing to follow proper protocol, did indeed suffer a concussion that night, and presumably just moments before the incident with Henderson.
Wideman and the NHLPA have launched an appeal.