SANTA CLARA — General manager John Lynch described it as a unique situation in which the 49ers had no other choice but to take action.

The 49ers officially voided the remaining guaranteed money in wide receiver Brandon Aiyuk’s contract early in training camp due to his failure to live up to the terms of his contract.

“There are basic rules, team rules, league rules,” Lynch said to NBC Sports Bay Area on “49ers Game Plan,” which debuted Friday. “I can tell you as a team, we don’t have many (rules). The ones we do are very important to us, and when they’re not adhered to —  this is the first time it’s happened in our tenure — we felt like we had no other recourse as to exercise those things.”

Lynch did not specify the rules that were broken that led the 49ers to void Aiyuk’s guarantee money. Aiyuk chose not to file a grievance to fight the 49ers’ action, The Athletic reported.

The 2026 option bonus of $24.935 million was subject to being voided if Aiyuk failed to report on time or be an active participant in any meetings or activities when instructed by the team, according to the contract, which NBC Sports Bay Area obtained through a league source.

Aiyuk sustained a severe knee injury on Oct. 20, 2024, against the Kansas City Chiefs. He underwent surgery in mid-November. Injured players are generally required to consent to frequent check-ins and rehabilitation under the direction of the team.

Aiyuk remains on the physically unable to perform list. There is no indication when, or if, the 49ers will open his practice window. After their game against the Cleveland Browns on Sunday, the 49ers will have only four remaining regular-season contests.

Lynch said Aiyuk continues to take part in physical therapy and he remains hopeful Aiyuk will again suit up for the 49ers.

“We want nothing more than for Brandon to come back and be a part of this team because he’s a really good football player, and he’s done a lot for our team, and we’re very appreciative for that, and we’re better when he’s on the field,” Lynch said.

The 49ers signed Aiyuk to a four-year, $120 million contract extension at the time. He was rewarded with the new deal following a 2023 season in which he caught 75 passes for 1,342 yards and seven touchdowns.

It is possible for the 49ers to get out of Aiyuk’s contract through trade or release in the offseason, with the team paying him a total of $49 million over two years.

Jauan Jennings, who has 37 receptions for 419 yards and four touchdowns this season, has been the 49ers’ top wide receiver in Aiyuk’s absence.

“Our guys have done a tremendous job of picking up the load when he’s been gone, and so we have enough, but it sure would be nice to add another piece,” Lynch said.

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