Johnson previously visited with the Seahawks but wound up leaving Seattle without an agreement in place.
Johnson, 26, is a former fourth-round pick of the 49ers back in 2014. He played out the final year of his four-year, $2,620,544 contract with the 49ers and has been testing the open market as an unrestricted free agent.
In 2017, Johnson appeared in all 16 games for the 49ers and recorded 77 tackles, one interception returned for a touchdown and seven pass defenses. Pro Football Focus has him rated as the No. 118 cornerback out of 120 qualifying players.