Bourne tested positive earlier in the week, but he has since passed multiple tests, so it appears as though this was a false positive.
The 49ers placed Aiyuk, Williams and Samuel on the list a few days ago for being in close contact with Bourne.
Williams, 32, 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.
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.
In 2020, Williams has started eight games for the 49ers at left tackle.
Samuel, 24, was the No. 36 overall pick by the 49ers out of South Carolina in 2019. He’s entering the second year of a four-year, $7,697,356 rookie contract that includes a $3,618,076 signing bonus.
In 2020, Samuel has appeared in four games for the 49ers and caught 16 passes for 185 yards receiving and one touchdown.