Mariners general manager Jerry Dipoto came to the Gaylord National Resort & Convention Center in search of a mid-rotation starting pitcher, and that search presumably continues as Heston figures more as organizational depth at this point.
Heston went 12-11 with a 3.95 ERA in 31 starts in 2015, but he threw just five innings for the Giants in four relief outings in '16 while allowing six runs on nine hits. He was 2-9 with a 4.54 ERA in 15 games, including 14 starts, for Triple-A Sacramento before going on the 60-day DL in June with an oblique injury.