As noted 29y old players with $10m left on their contract who do not play QB do not come expensive, you do not need to give up a 1st, especially the 19th overall pick, you are probably looking at a pick no higher than 3rd. The main reason is age and contract if Thomas is not offered a new deal by Seattle and they are happy to let him walk in 2019 they will get a comp pick for him but not until 2020, Seattle has a lot of $$ tied up in its defence and a lot of these players are not getting any younger. Seattle would prefer to get several of these contracts of their books and given a choice would prefer draft pick in 2018 rather than 2020, which would be lot better than any comp pick they would get in 2020.