Thus far, there has been no shred of evidence that the Mariners are “in” on any of the big name free agent starters. They have not been linked to Yu Darvish, Jake Arrieta, Lance Lynn, or Alex Cobb, and lack the farm system to pursue the likes of Gerrit Cole.
In other words, Jerry Dipoto must go outside the box to add potential impact to his rotation. While many free agent starter remain unsigned, Dipoto has shown a reluctance to sign free agents to long-term deals. This means that a trade is the most likely route.
Finding a team that is willing to part with starting pitching at a reasonable cost is difficult.