When a collision knocked Mike Smith's mask off, the Arizona Coyotes goaltender was less than pleased when he was told a few minutes later he had no choice but to leave the game.

One of the NHL's central spotters in New York made that call to trainer Jason Serbus, and in accordance with the league's concussion protocol, Smith's departure was mandatory.

"Mike didn't want to come out, but that's what was going to be done," coach Dave Tippett said. "I'm interested to see how that one goes in an overtime in playoffs or something like that. We'll see how teams react to that one."

The playoffs are still a month away, and teams are already not reacting well to concussion protocol for goalies, which is why it's one of the topics that general managers are expected to discuss at their annual March meeting beginning Monday in Boca Raton, Florida. Smith and New York Rangers goaltender Henrik Lundqvist are among those who have so far been critical of the rule.

Other issues include the offside rule, coach's challenges, goalie equipment and goalie emergencies as GMs try to refine rules they've put in place in recent years. GMs will talk about potentially not allowing coaches to call timeout after icing, which is being tested in the American Hockey League, and about allowing repeat players in the shootout after the first three rounds.

Video review is among the hottest topics, especially the time it takes. Major League Baseball recently instituted timing guidelines for umpires, and that could soon happen for hockey officials.

"That's probably maybe the No. 1 discussion," Dallas Stars GM Jim Nill said via phone Sunday. "Other than getting the call right, it is the timeframe. It's something we can't go seven, 10, 12 minutes to get it right. ... It is something where I think the call has to be done within a certain timeframe to keep the game going."

GMs will also discuss some disputed coach's challenges where a player's skate is off the ice and the play is ruled offside. It came up during a playoff series last year between the Chicago Blackhawks and St. Louis Blues and has been a subject of discussion at previous meetings.

Updates to the league's concussion protocol will be under the microscope after Smith and Lundqvist blasted the system as flawed. Connor McDavid and other skaters have expressed concerns with the rules that could have a major impact come playoff time — and goalies are at the centre of the debate.

"If there is an instance that takes place where you think there is a possible concussion, I think we need to look after that," Nill said. "When you do that, there's a risk of a player coming in cold. I guess the answer to that for me sometimes, it's no different than if a goalie hurts his knee, he's coming out and the other guy's coming in cold."

Goalie equipment and emergencies — where teams have to sign players to tryout contracts to back up for a game — are also on the agenda. After missing the past two meetings, George McPhee will attend as GM of the Vegas Golden Knights for the first time after owner Bill Foley's final expansion payment went through March 1.

GMs said criteria for the June 21 expansion draft have been made clear, so there's no need for further clarification. Blind-side hits, which were discussed at the November meeting, and playoff formats aren't on the official agenda but may be brought up over the course of the three-day meeting.

Ken Holland of the Detroit Red Wings has suggested expanding the playoffs to nine or 10 teams in each conference with play-in games similar to MLB, and the strength of the Metropolitan Division this season — where the fourth-place team has more points than the Atlantic Division leader — has generated some questions.

"I don't know that they want to keep changing it, but this is has got to be an impetus for at least a discussion when something happens like this where there's so many good teams in the one division," said Brian MacLellan of the league-leading Capitals, who acknowledged it would be self-serving to propose a change.