In 20 starts for the Mariners this season, Washburn is 8-6 with a 2.64 ERA. Washburn spent three-plus season with the Mariners after playing his first eight seasons with the Angels. He is 106-106 in his career with a 4.02 ERA.
French, 23, made his major league debut with the Tigers on May 15. He was 1-2 with a 3.38 ERA in seven games and five starts for Detroit.