In hockey, the term used is “maintenance day.”

It sounds like someone is taking his body to the auto shop for a tire rotation and a tune-up, but it mostly means a player was too sore to practice. By now no one questions it. Hockey is a physical sport. If you need to skip the day’s on-ice session to soak in an ice bath or get a massage, do it.

The question is why doesn’t it happen on game days?

Maybe it should. Maybe it is and we just don’t know.

Two days after Auston Matthews was a game-time decision and played in the Toronto Maple Leafs’ 4-3 overtime shootout win against the Vegas Golden Knights, and one day after he missed practice with “soreness,” the best player on the Toronto Maple Leafs will not play Wednesday night against the Minnesota Wild. The official word from head coach Mike Babcock is that Matthews is day-to-day with an upper-body injury.

The unofficial word was that he needed a break. And few could blame him.

This is a brutal part of the schedule for the Maple Leafs. After playing four games in six nights on the road last week — three in California and one in St. Louis — they returned home for another four games in six nights this week. In total, they play eight games in 13 days, including two sets of games on back-to-back nights.

If this were the middle of March, perhaps whatever is ailing Matthews wouldn’t have kept him out of the lineup. But if you are going to miss a game to rest a bump or a bruise, better to do it in the second week of November when the points in the standings don’t seem as dire.

“I think you’re never going to feel 100 per cent,” Matthews said after Monday’s win against Vegas, in which he had an assist and logged a game-high 21 minutes and 11 seconds among forwards. “But I felt good enough to play and good enough to contribute.”

It was another way of saying that he had gutted out and played through whatever was bothering him. He might have done the same on Wednesday, except he either couldn’t or was advised not to for fear of the injury becoming worse. Whatever the reason, he took the night off and it wasn’t a big deal — or at least it should be.

The Leafs won’t play goalie Frederik Andersen in every game this week, because they don’t want him to burn out. But if Andersen needs rest, why doesn’t Matthews, who is averaging a minute more in ice time than any other Toronto forward and plays in all the critical situations?

The answer has more to do with hockey’s warrior mentality than any stats-based reasoning.

Yes, you need Matthews on the ice to win games. He is a top-5 scorer in the league with 10 goals and 19 points in 16 games this season. He already has two game-winning goals and assisted on another. Draw up a list of the Hart Trophy candidates so far and his name would be on it.

Even if he is hobbling, Toronto is a better team with Matthews in the lineup. But you could say the same thing about Andersen, who provides Toronto with a far better chance of success than backup goalie Curtis McElhinney.

The only difference is that it’s become acceptable for starting goalies to get the second night of a back-to-back off. Asking a forward or defenceman to do the same runs counter to a hockey culture where players hide concussions and huff smelling salts on the bench. That could explain why the league introduced mandated periods idle periods for each team. (The Leafs have one game in an eight-day stretch in March, for example.) Without them, players like iron man Andrew Cogliano who played in his 800th consecutive game this week, would never sit out.

It’s not like this in the NBA, where resting star players has gone from that quirky thing that the San Antonio Spurs did to what’s now become an accepted practice. Every team does it to some extent. Of course, it’s easier to do in a sport where teams like the Golden State Warriors have already locked up a playoff spot by November.

The NHL has far more parity so it’s a risk for any team to go into a game with a disadvantaged roster. Every point, whether it’s in October or April, matters in the standings. At the same time, taking one player off an NHL roster should have less of an impact as taking a player off an NBA roster, since NHL rosters are bigger and their star players are on the ice significantly less than NBA stars.

In the past, the Pittsburgh Penguins have won gone weeks and months without Sidney Crosby or Evgeni Malkin in the lineup and not missed a beat. The Montreal Canadiens are undefeated in the three games that Carey Price has been out with a lower-body injury, while the Ottawa Senators were without Erik Karlsson for their first five games of the season and earned at least a point in all five.

While Matthews is important to the Leafs’ success, this is a team that has so much depth that Mitch Marner has been playing on the fourth line and NHL-calibre players such as Josh Leivo and Kasperi Kapanen are unable to get into the lineup on a regular basis.

Toronto should survive. And Matthews, whenever he is healthy — or well-rested — will be the better for it.

• Email: mtraikos@postmedia.com | Twitter: @Michael_Traikos