Filip Chytil, left, and K'Andre Miller of the New York...

Filip Chytil, left, and K'Andre Miller of the New York Rangers collide during the second period against the San Jose Sharks at Madison Square Garden on Thursday. Credit: Getty Images/Bruce Bennett

The Rangers leave Saturday for a four-game trip to the Pacific Northwest and Alberta. And if Filip Chytil doesn’t make the trip with the team, that spells trouble. Big trouble.

Chytil, who missed the final 72 games and the first round of the playoffs last season with what was described as an upper-body injury — and presumably was a concussion — didn’t play in the third period of Thursday night’s 3-2 win over the San Jose Sharks after he was knocked to the ice in an inadvertent collision with teammate K’Andre Miller in the second period.

Chytil was slow to get up after the hit and left the ice for the locker room. He returned to play one shift before the period was over but didn’t come back for the third.

“I have no idea what’s going on with him,’’ teammate Vincent Trocheck said after the game.

Coach Peter Laviolette gave the standard “he’s being evaluated’’ report after the game. Because the Rangers were not scheduled to practice Friday, no update was given.

It’s possible that Chytil was fine and that the Rangers made the decision that with a 3-1 lead and the 25-year-old’s history of concussions, they would be cautious and not play him in the third period. If that’s the case, however, why would they have played him for one shift late in the second?

It’s also possible that Chytil was cleared to return, played a shift (he looked fine, by the way) and then didn’t feel right somehow, so the team decided to hold him out.

And if that’s the case, that would be hugely concerning — mostly for the player but also for the team.

The Rangers have never disclosed when (or whether) Chytil has had a concussion, but he’s believed to have had several. He missed three games in November 2021 after a collision with then-teammate Sammy Blais and missed games in April of that season with an upper-body injury. He missed six games in 2022 after taking a shoulder to the head in a game against Columbus in October. And last season, he left practice one day during training camp and missed the rest of the preseason with what the team said was an upper-body injury.

Then he bumped into Carolina forward Jesper Fast in a game last November, and that effectively ended his season. He tried to return and was working his way back in late January when he suffered a setback in a morning skate that shut him down for good.

Were those all concussions? We don’t know.

So the health of the player is the primary concern. But Chytil also was playing well and centering the Rangers’ best line this season, between Will Cuylle and Kaapo Kakko. That line has outscored opponents 11-0 and been a difference-maker for the Rangers (10-4-1). Chytil has four goals and five assists.

On Wednesday, Laviolette praised the line after its two-goal performance in Tuesday’s 6-3 loss to Winnipeg, saying, “They played a real simple game, that line. They got it out, they got it through the neutral zone, they put it in. They sent pucks at the net, people at the net, chipped in a couple goals. They’re playing pretty well defensively, also. [Their play] probably warrants more time, more minutes.’’

Chytil drives most of the play on that line. If he is out with a concussion — or out for an extended period for any reason — that would be a massive blow to the team.