Tim Tebow not having a sports contract with a team did not stop Adidas from signing him to a multiyear deal. It was Tebow star power that caught the shoe company interest. It appears that Tebow had been in talks with sign for a while but trying out for baseball was the added push.
It’s not unprecedented for shoe companies to sign people to contract without them having a sports contract. With all the interest that Tebow has drawn with his baseball tryout this makes sense.