Gilmartin was designated for assignment by the Rays on Sunday, Juan Toribio of MLB.com reports.
The 30-year-old was previously DFA'd by Tampa Bay a couple weeks ago, but he accepted his outright assignment and rejoined the big-league club Saturday. Gilmartin has appeared in two games this season, allowing four runs on seven hits with a 5:4 K:BB over 4.1 innings.