SANTA CLARA, Calif. — One season shy of landing a coveted spot on the wall in the San Francisco 49ers’ facility that celebrates those who have played at least 10 years with the team, defensive lineman Arik Armstead is expected to become a free agent.

A source confirmed to ESPN’s Adam Schefter on Sunday night that Armstead and the Niners attempted to work out a restructured contract and that, after coming close but failing to reach an agreement, Armstead is expected to be released and become a free agent.

Armstead is coming off a season in which he played in 12 games with 27 tackles and five sacks. Be he also is slated to count $28.53 million against the 2024 salary cap, which is why the Niners were seeking a reworked deal to reduce that number.

While releasing Armstead would save the 49ers around $18.2 million in cash for next year, they would incur a dead money charge of $25.86 million and save only $2.492 million against the cap with an immediate release. The Niners could, however, save more than $18 million against the cap if they add the post June 1 designation, which would spread that remaining dead money over future years.

As Armstead prepares for the potential of his second foray into unrestricted free agency, he also is coming off a torn meniscus in his right knee, an injury he suffered in a Dec. 3 win at the Philadelphia Eagles. Armstead finished that game after suffering the injury on the second play, but he did not play again until the Jan. 20 NFC divisional round win against the visiting  Green Bay Packers.

He was listed on subsequent injury reports with knee and foot injuries (plantar fasciitis), but he said after the season that the knee issue was the more problematic of the setbacks.

“I thought my season was over with after the Philly game,” Armstead said on Feb. 13. “I tore my meniscus and didn’t know if I was going to be able to come back and put in a lot of hard work to get back for the playoffs.”

Armstead did appear in all three of San Francisco’s playoff games, posting 11 tackles, a sack, seven quarterback pressures and a fumble recovery on 148 snaps. He said in February that while knee surgery will require a lengthy recovery, his hope is to be ready to return sometime in late July or August as training camps get underway.

San Francisco originally used the No. 17 pick in the 2015 NFL draft on Armstead. He began his career as a defensive end, but after dealing with myriad injury issues early in his career, he transitioned into an interior role in 2019. A breakout 10-sack season that year helped him land a five-year, $85 million deal early in 2020 free agency.

Over nine seasons in San Francisco, Armstead played in 116 regular-season games, posting 33.5 career sacks. He also has appeared in 12 postseason games, registering eight sacks.

A native of nearby Sacramento, Armstead is not only San Francisco’s longest-tenured player, he has been a philanthropic staple in the Bay Area and in his hometown. For the past four years, he has been the Niners’ nominee for the Walter Payton NFL Man of the Year Award.