The United States club have confirmed that he will be added to their roster pending receipt of his P-1 Visa and international transfer certificate. League and club policy means no details of the deal are disclosed.
"Tyrone is a player we had an opportunity to evaluate over the summer when he trained with us in Seattle and we were very impressed with his pedigree," said head coach Sigi Schmid.
"He is a full back that is solid defensively, with the ability to posses the ball and to get forward in the attack.
"Tyrone is also a very good one-versus-one defender, a capability that is a key ingredient to success in our league, and we're excited about his future with our club."
Sporting Director Chris Henderson added: "His professional experience, athleticism and versatility on the backline make him a valuable player for our club heading into 2015."
Mears joined Burnley from Derby in the summer of 2009 following our promotion to the Premier League. He played in all of our Premier League games and added a further 44 league appearances in the following season.
He, along with Chris Eagles, had been looking for a return to the Premier League and took it when former Burnley boss Owen Coyle took them to Bolton in a big double transfer deal, but he suffered a serious injury in his first season and then, on his return, fell out of favour with then manager Dougie Freedman. In total he made just 28 league appearances for them before being released last summer.
Now aged 31, he is looking to rebuild his career in Seattle.