Amongst these Mariners are Domingo Santana, Mitch Haniger, Mallex Smith, and Omar Narvaez. All are under club control for at least 2.5 seasons, while the latter three are under club control for 3.5 seasons.
All these players carry different value, but they are the most likely to fetch high return thanks to their low salaries and club control. Perhaps the most interesting case of the players mentioned above is Omar Narvaez.
An offense-first catcher, Narvaez has the 6th highest wRC+ amongst MLB catchers and may just be available for teams looking for the offense of any kind from their catcher position.