Heston is just a season removed from posting excellent numbers (12-11, 2 CG, 1 SO, 3.95 ERA in 31 starts) for the Giants, so this is a good gamble for the Mariners. Heston will probably compete (and win) the No. 5 role in Seattle's rotation out of spring training.

For the Giants, this was a move designed to give Heston a better shot at a regular spot in a starting rotation in MLB, as he made only four appearances (0 starts) with the big club in 2016. San Francisco's rotation has younger options for the No. 5 spot in the rotation.

A bounce-back campaign could be in Heston's future, especially if he adjusts well to pitching in the American League. He moves from pitchers' park to pitchers' park going from AT&T Park to Safeco Field, so his fantasy value remains intact.