On March 14, 2018, Richburg signed a five-year, $47.5 million contract with the San Francisco 49ers.

In Week 14 of the 2019 season, Richburg suffered a torn patellar tendon and was ruled out for the rest of the season.
He was placed on injured reserve on December 11, 2019.
Without Richburg, the 49ers reached Super Bowl LIV, but lost 31-20 to the Kansas City Chiefs.
He was placed on the active/physically unable to perform list at the start of training camp on July 28, 2020.
On March 14, 2018, Richburg signed a five-year, $47.5 million contract with the San Francisco 49ers.
In Week 14 of the 2019 season, Richburg suffered a torn patellar tendon and was ruled out for the rest of the season. He was placed on injured reserve on December 11, 2019. Without Richburg, the 49ers reached Super Bowl LIV, but lost 31-20 to the Kansas City Chiefs. He was placed on the active/physically unable to perform list at the start of training camp on July 28, 2020.
Weston Richburg