Williams is entering the final year of his deal that San Francisco inherited after trading for the veteran from Washington. He is scheduled to be a free agent in 2021.
The restructured deal advanced Williams half of his money upfront in a guarantee after he gave up his entire salary last year.
Williams was set to make a base salary of $12.5 million in the final year of his deal.
After San Francisco traded for Williams, the expectation is that the two sides will allow the 2020 season to play out before evaluating a potential extension. This gives Williams a considerable amount of leverage in any talks.
Williams, 31, is a former first-round pick of the Redskins back in 2010. He currently in the final year of his five-year, $66 million contract that includes $43.25 million guaranteed and stands to make a base salary of $12.5 million for the 2020 season.
In 2018, Williams started 13 games for the Redskins. Pro Football Focus rated Williams as the No. 21 tackle out of 80 qualifying players.