Why it makes sense for St. Louis in the short-term:
This trade may be far more realistic come the offseason, but the Cardinals and Mariners continue to feel like the answer to each other's questions, and whether it is Bryan Woo or one of the seemingly endless set of arms the Mariners have on their roster, the Cardinals would be wise to acquire one.
KMOV's Brendan Schaeffer and I briefly discussed on our new podcast "Philosophical Differences" how the Mariners and Cardinals seem like that match made in heaven on paper, but in practice, both sides are going to have a hard time coming to an agreement due to how they value each of their bats and arms. There isn't a clear one-for-one swap that makes sense for both sides, so one side will likely need to include a kicker to get something done if they ever did. Still, with how desperate the Mariners are for offense, they may have to change that tune.
I'm sure the Mariners would much rather take Emerson Hancock and another piece to acquire someone like Gorman, but in this scenario, I am going to have the Cardinals taking Gorman and Thomas Saggese to acquire Mariners' starter Bryan Woo.
Woo debuted for Seattle last year, posting a 4.21 ERA in 18 starts, flashing his electric stuff in the process. Woo has battled an injury this year but has stepped up his game even more, posting a 2.54 ERA in his 10 starts. Woo still has room to grow in his game in terms of missing bats, and if he is able to get more punchouts as the years go on, he could be a future front-line starter. The results certainly feel like one right now.
Why it makes sense for St. Louis long-term:
The Cardinals have young arms coming in Tink Hence, Quinn Mathews, and Cooper Hjerpe along with others, but getting a guy in their rotation now with upside and control would be a major get. It would be fun to swing higher for George Kirby or Logan Gilbert, but I really do not see the Mariners parting with either of them any time soon.
The Mariners' offense is so bad right now, and they just had Julio Rodriguez land on the injured list as well (not that he's been all that great either). They need to add multiple pieces to this offense at the deadline, and Gorman would be a valuable start. His inconsistencies won't be pleasant, but his ability to take over games with his power would be huge for Seattle.
I've already said it a few times, but losing one left-handed bat is not the end of the world for the Cardinals. This scenario would actually allow St. Louis to bring back Ivan Herrera and DH him frequently with the at-bats that need to be covered, and assuming they add another right-handed bat for the outfield, Donovan can slide back to second base. Gorman has been underwhelming overall this year, so while he still could produce down the stretch, the Cardinals aren't losing someone who is currently producing.