On Tuesday, Albert Breer of The MMQB reported Davis signed a one-year, $775,000 contract. Breer noted he got a $50,000 signing bonus and will get a $30,000 bonus if he makes the team.
Davis has 10 career starts and hasn't appeared in a game since 2015.
The 28-year-old spent the past season with the Denver Broncos behind Trevor Siemian and Paxton Lynch on the depth chart.
Since joining the St. Louis Rams as an undrafted free agent in 2012, Davis has appeared in 13 games, totaling 13 touchdowns and 12 interceptions.
Meanwhile, Kaepernick has notably remained unsigned throughout the offseason despite a solid season on the field in 2016. Seahawks coach Pete Carroll told reporters Friday that Kaepernick is "a starter in this league."
However, that clearly wasn't enough to sign the 29-year-old, who made himself a divisive figure in the NFL when he chose to kneel during the national anthem.
Gregg Bell of the News Tribune provided an explanation on the team's decision:
The Seahawks released Jake Heaps to complete the move, meaning Davis will compete with Trevone Boykin for the second-string job.