Garton agreed to a minor-league contract with the Mariners on Friday which includes an invite to spring training.
Garton appeared in 20 major-league games split between Tampa Bay and Seattle in 2017, posting a 4.91 ERA and 1.09 WHIP with a 16:6 K:BB in 22 innings of relief. The 28-year-old will get an opportunity to claim a spot in the bullpen heading into 2018, but Triple-A Tacoma is a likelier bet.