Dennis Wideman was found to have a concussion after the Calgary Flames' game against the Nashville Predators last week, but the league says that doesn't excuse his cross-check on linesman Don Henderson.
"Wideman is hit hard by the Salomaki check and it is accepted for the purposes of this decision that he was later diagnosed as having suffered a concussion," the NHL acknowledged in a video explanation Wednesday.
"However, that fact - even accepted as true - cannot excuse Wideman's subsequent actions."
Wideman was suspended 20 games on Wednesday, and the players' union has already begun the appeal process.
The Flames could be fined if the league determines the club failed to follow concussion protocol, TSN's Rick Westhead reports.
Flames president of hockey operations Brian Burke said in a statement Wednesday that Wideman's hit on Henderson was "unintentional" and "accidental."
The blue-liner will forfeit more than $500,000 under the terms of the NHL's CBA.