Finding a direct, 2-team trade is difficult in and of itself. Finding such a trade when a team with a bad farm system is trying to acquire a young star is almost impossible. At first light, the most obvious trade would appear to be a straight Mitch Haniger for Blake Snell swap.
Both have lots of club control and both are young All-Stars. Haniger is 2 years older than Snell, but Snell is a pitcher, therefore a higher risk of injury in the future. But for the Mariners, does this actually make them better? At best, it is probably a wash. Tampa might prefer their own guy too. So the Haniger for Snell thought quickly falls on its face.
Next, you could think about something like Marco Gonzales and Kyle Lewis for Snell type of deal. Gonzales is having a nice season and is just a few months older than Snell. Lewis is the Mariners top prospect and finally looks healthy after a torn ACL injury basically wasted a year and a half of Lewis’ career.
While in this scenario Seattle does get better in 2018, Tampa is likely to balk at this offer. Sure, Lewis is a nice prospect. But having already suffered a major injury and never taking an AB above High-A ball, it is still quite a risk. Plus, Gonzales has already suffered through 1 Tommy John Surgery, so Tampa probably looks at him as damaged goods as well.
You can keep stacking prospects onto either deal, but Tampa isn’t going to be wowed by the number of prospects they can get for Snell if they aren’t “impact guys”.
At the end of the day, Seattle cannot do this alone (probably not at all). So, in true Jerry Dipoto fashion, we need to get creative. We need a 3rd team.