Ethan Finlay was able to joke about his botched celebration after scoring the insurance goal in the Loons’ 3-1 win over Real Salt Lake at Allianz Field last Sunday. But the eight-year MLS veteran was dead serious about the expiring collective bargaining agreement.

A member of the MLS players association’s executive board, Finlay detailed his side’s concerns when the contract expires in January. So far, he said, there have been only informal talks between the players’ union, MLS and its club owners. Formal negations will commence closer to the Jan. 30 expiration date.

If an agreement isn’t reached, Finlay has been communicating with teammates as United’s union representative.

“I think we have a very informed player group and they understand what a strike would look like,” Finlay said. “We have played scenarios out and helped guys get all their ducks in order. That stuff has already started and is already in place.”

This week, most of his communication with teammates has been decidedly less serious. Since he attempted a knee slide celebration after the game-sealing goal in a pivotal Western Conference match, Finlay has been the focus of a lot of good-natured ribbing.

The Allianz Field turf wasn’t as slick as Finlay expected, so his knees dug up a divot and he tumbled forward. Before Finlay was back at his locker, United’s video analyst Sam Lawson already had clipped it and sent it out on the team’s group chat thread.

One Reddit poster made it a meme: “Sliding into Monday like …”

“I’m just happy I got out of that one without an injury,” said Finlay, who tore the anterior cruciate ligament in his knee last April.

Second on the team with seven goals going into Sunday’s game at Portland, Finlay was a good sport about the very public fail. “I’m surprised that wasn’t a ‘Not Top 10 moment’ ” on SportsCenter, he said. “I’m glad I lucked out on that.”

Teammates, he noted, were kind on social media but let him have it in private.

“You have to take those moments,” he added. “It’s a fun, happy moment because I scored the goal, so I can take the flack — deservedly so.”

But Finlay isn’t joking about the CBA. The union’s major issues are getting more options for player movement through free agency and otherwise, and increasing clubs’ salary budgets and the transparency about the money teams have available.

To a lesser degree, Finlay said, the union would like more charter travel; clubs now only have four legs available each season and otherwise fly commercial.

Finlay said he’s spoken with reps for other clubs and feels confident they’re prepared for a potential work stoppage.

But the question is, do the players have the necessary leverage?

“We have 600-plus players that we represent and we have to try to all make happy,” Finlay said. “There are 26 ownership groups” with Miami and Nashville beginning play next season. “They have (fewer) people than we do. Our job is very difficult.”