If the past 2 major Mariners moves to prove anything, it is that this rebuild will be anything but conventional. First trading Ben Gamel with 4-years of club control for Domingo Santana, who has 3 years of club control. In a traditional rebuild, club control and prospects are kings. The Mariners sacrificed a little of both in this trade.
Second, the Yusei Kikuchi signing. Spending “big money” when you are sacrificing at least 1 season is unusual. Especially when you consider the player in question is completely unproven in MLB. But the Mariners signed him to get his feet wet in the rebuild, with the idea he will be comfortable when they compete in 2020 or 2021.