The Los Angeles Football Club was already in the market for center backs. Then team captain and defensive anchor Aaron Long ruptured his left Achilles tendon on Saturday night, making that a priority.

After going down in the 76th minute of LAFC’s 2-0 victory over FC Dallas at BMO Stadium, Long, 32, underwent successful surgery on Monday evening to repair an injury that wasn’t immediately apparent to people in the stands or the press box.

On the field, though, there was no mystery.

“For me, as soon as I saw his face on the ground in the game, I already noticed what was happening,” said fullback Sergi Palencia, who has played together on the backline with Long and fellow outside back Ryan Hollingshead for most of the past two-plus seasons. “It was so sad. Not only are we going to miss him so much on the field. Off the field, also, he is a huge part for us.”

Long appeared in 104 matches in all competitions after joining the club as a free agent in 2023. Named captain in his third season in L.A., Long’s joking manner and way of speaking endeared him to the group as much as his sustained, hard-nosed play.

“As a footballer you just know how quickly it can be taken from you,” Hollingshead said. “And so you watch one of your best buds and captain and starting center back and such a rock for our defense go down like that in that way, and especially grueling for him because he’s dealt with this injury before, so it’s something that he knows well.”

In May of 2021, with the New York Red Bulls, Long ruptured his right Achilles tendon while landing from a jumping header.

Eight months later, he was back to training at full speed.

“He’s going to be in the gym showing the young kids what it’s like to recover from an injury,” a hopeful Hollingshead said.

Unavailable from the midway point of the season on, Long’s rehab gets underway as his team faces an important midweek trip to second-place Minnesota United FC, which has played three more MLS games than LAFC (9-5-5, 32 points) and is eight points above coach Steve Cherundolo’s club in the Western Conference standings.

Opening league play by beating Minnesota, 1-0, on Feb. 22 at BMO Stadium, Cherundolo had five of the roster’s seven center backs listed on the team sheet, starting Long next to Marlon Santos.

Cherundolo is likely to have three tonight at Allianz Field against the Loons (11-4-7, 40 points) — Eddie Segura, Nkosi Tafari and first-team contracted LAFC2 regular Kenny Nielsen, a 23-year-old Irvine native who is in line to make his MLS debut.

Placing Long on the season-ending injury list means LAFC gets roster relief and can sign a player of equal value on top of the money it saved with the departures of Olivier Giroud and Marlon. Ahead of the summer transfer window, those resources, including $750,000 in general allocation money plus several million dollars in winnings from the FIFA Club World Cup prize pool, should go toward shoring up positions across the field.

Meanwhile, current players — including Long, who played 375 of LAFC’s 390 Club World Cup-related minutes — will split $1.8 million from the CWC excursion.

On Tuesday, The Athletic reported a deal had been struck on June 27 between MLS and the players’ association.