The Rays love making these kinds of trades
The number one reason that this trade could happen is because of the Rays’ tendencies to sell high on their star players, even when they are competing. Years ago the Rays traded James Shields after a 90 win season and then traded David Price a few years later.
Recently they have made a few similar trades. In 2017 they traded their franchise third baseman Evan Longoria to the San Francisco Giants. In 2018 they traded their Opening Day starter Chris Archer in the middle of what became a 90 win season to the Pittsburgh Pirates for Tyler Glasnow (Their current number 2 starter), Austin Meadows (Current starting outfielder), and Shane Baz (Their number 5 rated prospect).
They also traded Tommy Pham to the San Diego Padres this past offseason in a deal that sent prospects and MLB players both ways. The Rays also sent Jake Cronenworth to the Padres in the deal and received Hunter Renfroe (Who the Rays just DFA’d), Xavier Edwards (Their number 4 rated prospect), and a player to be named later.
A trade for Snell that would involve multiple Mariners prospects and MLB ready players would definitely be something that the Rays would listen to. Snell has 3 years left on a deal that still owes him $39 million, so the small-market Rays could be interested in a deal if the Mariners offer the right price which we know they can with their stacked farm system.