The Mariners just made a surprise trade with the White Sox that no one saw coming

We all thought that the Mariners would be going after another reliever at some point this offseason. We saw them move on from a couple of them in trading away both Justin Topa and Isaiah Campbell this offseason. The Mariners needed to add somebody, and plenty of fans thought that it was going to be for a free agent. Maybe it was going to be one of the minor leaguers. Maybe it was a trade. We really didn't know.

Then, without any fanfare or rumors about it, the news broke that the Mariners had required a young and dominant reliever to add to their pen in a deal with the Chicago White Sox.

It caught everyone off guard. It's a lot to take in, and a move like this can be hard to originally process as a Mariners fan. You see a draft pick involved (nice), and then two players that you are familiar with. We had heard that DeLoach might be a person to watch in Spring Training as fighting for an outfield spot. Then, there was Prelander Berroa. He instantly got better after getting here in the deal with the San Francisco Giants, and was thought to be getting serious consideration for work in the pen in 2024.

Seeing names like that leave makes you wonder. But, you have to think about the value that they actually represented in 2024, and what kind of value the team is getting back. Santos is under team control through 2028, which means that the Mariners are going to have him for 5 full seasons. What exactly are they getting?

Well, Santos threw 66 innings last year for the Sox, and was in line to be their closer in 2024. He had a good ERA of 3.39, but way more impressively, he had a FIP of 2.65. That's exceptional, especially when you see the BABIP of .337, 44 points worse than the league average. It's a good sign.

He throws a slider and sinker, with those pitches taking up 96% of his usage. The sinker is nasty too, getting up to 100 and sitting with an average velo of 98.9 mph. The slider brings heat too, sitting at 91.4 mph. You are adding a third nasty boy to the Mariners pen, and those final three innings have a chance to be incredibly dangerous.

While this isn't an acquisition to the likes of Devin Williams, it's a great get for the Mariners, even if it is surprising. If his elbow can hold up, the Mariners just got a lot better for 2024.