The San Francisco 49ers are trying to finalize a deal with Trent Williams, league sources told ESPN's Adam Schefter, as the star left tackle's holdout continues.

Social media posts from Williams' brother indicated that the 11-time Pro Bowler returned to the Bay Area on Monday night, a week before the Niners open their regular season against the New York Jets on "Monday Night Football."

Williams, 36, has held out of San Francisco's entire training camp as part of his contract dispute, accruing more than $4 million in fines for missing every practice and three preseason games. He is owed $20.05 million this season under the six-year, $138.1 million deal he signed in 2021.

The Niners left Williams off their 53-man roster last week, keeping the three-time All Pro on the reserve/did not report list. San Francisco created over $5.4 million in salary cap space Tuesday, according to ESPN's Field Yates, by restructuring the contract of defensive lineman Maliek Collins.

The ramped-up negotiations between Williams and the 49ers come less than a week after the defending NFC champions resolved a similar contract dispute with star receiver Brandon Aiyuk, who signed a four-year, $120 million deal that includes $76 million guaranteed.

Widely considered the NFL's top offensive lineman, Williams has an average annual salary that ranks sixth-best among tackles after Tampa Bay's Tristan Wirfs, Detroit's Penei Sewell and Minnesota's Christian Darrisaw all signed big-money deals this offseason. Houston's Laremy Tunsil and the Giants' Andrew Thomas also make more than Williams in terms of average annual salary.

Williams' deal also includes no more guaranteed money, though the 49ers are still on the hook for nearly $30 million in signing bonus proration through 2027 because of restructures they have done on the contract.

Williams ranked as the best pass blocking tackle in the NFL in 2023, with a 95.8% pass block win rate. The Niners averaged 6.05 yards per carry when rushing behind Williams to the left side last season, while averaging 4.45 yards per attempt on all other rushing attempts.

Last season, Williams missed two games, played through injury in another and played only 12 snaps in a meaningless Week 18 game against the Rams. The 49ers were 0-4 in those games and 12-1 in all others.

ESPN's Nick Wagoner and The Associated Press contributed to this report.