Indulge me for a minute, if you will. In my fantasy football league, one league member grew infatuated with trades this season. He made six swaps in three weeks, overhauling his whole team and inundating my phone with negotiations and trade proposals. To a certain degree, it worked — he managed to put together a really solid team with a bunch of great players. But there was one trade that he sincerely regretted, and if he hadn’t pulled the trigger, he’d be in the playoffs as opposed to watching from home.

I mention this not to bore you but to instead draw parallels to Jerry Dipoto and the Seattle Mariners. Dipoto clearly loves making trades, and many of these swaps have turned out quite well for the M’s. His latest deal, however — flipping Jean Segura, Juan Nicasio, and James Pazos to the Philadelphia Phillies for J.P. Crawford and Carlos Santana — feels to many like a trade made just for the sake of making trades. And it’s led to a whole host of criticism as a result.

Let’s try to understand what Jerry Dipoto was looking at when he pulled the trigger on this trade by looking at some surplus values for each player involved. Surplus value, for those of you who don’t live and breathe Fangraphs, is basically a unit of measurement that allows us to compare players’ projected production with the salaries that they’re being paid.

First, the Phillies’ side of this:

Jean Segura is under contract from 2019–2022, with a team option for 2023. Each of those first four years comes at $14.2 million a pop. Segura was worth 3.8 fWAR last season and has averaged about 4 fWAR across the last three years. His atrocious 2014 & 2015 seasons are likely keeping his projections down, however, as Steamer pegs him for just 2.6 fWAR on a .284/.330/.414 slash line. We know, though, that part of those struggles was personal tragedy, and that Segura’s true talent has improved with a swing change since then. If we split the difference, he becomes a 3.2 fWAR player — that feels about right.

Since Segura will be just 29 years old next season, I imagine he’ll keep his value for each of the next two or three seasons and start to drop off after that. I’m going to put him at 3 wins for each of the next three seasons and 2 for the fourth year, which gives him 11 fWAR of value. Based on the free agency $/WAR projections from this article, and then subtracting the $58 million he’s owed for those seasons, Segura represents ~$48 million in surplus value.

Juan Nicasio’s surplus value is much easier to figure out. Nicasio has one year left at $9 million. He struggled last year with an ERA of 6.00, but his underlying metrics are strong — hitters posted a .402 BABIP against him. Despite that, projections are bearish, putting him at 0.2 fWAR. In that case, Nicasio is roughly -$7 million in value, though I can easily see a situation in which he’s much closer to neutral.

in value, though I can easily see a situation in which he’s much closer to neutral. James Pazos is under club control for four more seasons, making the league minimum in 2019 before he’s arbitration-eligible from 2020–2022. His velocity drop last season is certainly concerning, but Steamer calls him a 0.2 fWAR pitcher next season. For the sake of simplicity, let’s say Pazos will be worth 1.5 total fWAR over the next four years combined (which might be aggressive), and he’d be paid something like $8 million in those years. So he’s got roughly $5 million in surplus value.

That’s a total of $46 million in value going to the Phillies. But the M’s?

Carlos Santana is a projections darling. He’ll be 33 next season, but his on-base skills shouldn’t go anywhere, and that’s why Steamer calls him a 2.5-win player who will hit .241/.357/.435. Of course, he’ll be paid as such, making $35 million over the next two years. If we ding him a half-win in 2020 as he ages, then he’ll be worth $41.5 million in value those two seasons, giving him $6.5 million in surplus value.

All this is to say: In order for this to be an even trade on the surface, J.P. Crawford has to be worth roughly $40 million in surplus value for the Mariners. But that includes Santana as an asset; if we assume the Mariners aren’t trying to win in 2019, his production there becomes almost meaningless, thus costing the Mariners $17 million in pure salary.

There have been legitimate concerns about Crawford’s bat and about his shortstop defense thus far in the bigs. There’s a reason that free agents are so expensive: their production is much more guaranteed than what prospects will put up. It’s not unreasonable to imagine Crawford hits his projection of 1.9 fWAR next season and is a 2-win player for each of the five seasons after that (I’m assuming the Mariners will keep him down in AAA until mid-May to gain an extra year of control). It’s also possible to imagine him becoming a star and doubling that projection, or failing to produce and barely getting into positive WAR value.

Let’s go with my first assumption, that he’s a 2-win player for each of the next six seasons:

This is basically modern-day back-of-the-envelope math, but it checks out. Crawford could very well put up nearly $100 million in surplus value, and that would make him incredibly valuable to a team trying to re-load. It would also more than cover the value of the players that Dipoto sent to Philly.

The takeaway, therefore? If J.P. Crawford isn’t starting for the Mariners at shortstop in 2021, then this is almost certainly a failure for the M’s — and there’s a decent chance Jerry Dipoto won’t be the general manager as a result. If he truly is a “post-hype sleeper” who can man an infield spot for years to come, then this bet will pay huge dividends for the M’s.

Trader Jerry is betting big on “his guys,” from Mallex Smith to Jarred Kelenic and now Crawford. If it works, the next great Mariners core is already here, and playoff contention is around the corner. If it doesn’t work, there won’t be much joy in Mudville, for mighty Jerry will have struck out.