Keith was assessed a match penalty for intent to injure and is suspended indefinitely. He was knocked to the ice by Coyle and retaliated by swinging his stick while lying on the ice. Coyle was left with blood dripping down the bridge of his nose.
The NHL's Department of Player Safety tweeted Wednesday that Keith has been offered an in-person hearing.
The penalty, at 9:27 of the first period, left the Blackhawks short-handed for five minutes, though the Wild did not score during the extended power play. It also left the Blackhawks without two key defensemen;Brent Seabrook missed the game because of illness.
The Wild won the game4-1.
Because he was assessed the match penalty, Keith is suspended until the league reviews the play. Keith's case won't be helped by his previous suspension, in the 2013 playoffs, for swinging his stick and hitting Los Angeles Kings forward Jeff Carter in the face.
"We miss guys all year long. I'm not worrying about hypotheticals," Chicago coach Joel Quenneville said about a possible multiple-game suspension.
The Blackhawks visit the Winnipeg Jets on Friday night.
Duncan Keith ejected for swinging his stick
Blackhawks defenseman Duncan Keith is given a match penalty and, by rule, suspended indefinitely pending a review after he swings his stick and hits Wild center Charlie Coyle in the face during the first period.
Keith ejected in loss to Wild
Chicago's Duncan Keith was ejected for swinging his stick and hitting Minnesota's Charlie Coyle in the first period. In the game, the Wild score three times in the third period to win 4-1 for their sixth consecutive victory.