The Rays designated Seymour for assignment Thursday.
Seymour saw extended big-league action to close the regular season, and he slashed .205/.253/.282 with a 38.6 percent K rate across 83 plate appearances. It was a disappointing MLB debut for the first baseman who launched 30 homers at Triple-A Durham before being called up. He'll now be exposed to waivers, though he could remain with the Rays if he goes unclaimed.