The Contract
Five years and $155M, covering ages 31 to 35. Every one of those is a decline-risk year. The question is whether the production shows up.
The anchor
The base case is not this site's guess. It is the ZiPS projection FanGraphs published in December 2025 at signing, which valued the deal near $110M against a $155M guarantee.
| Year | 2026 | 2027 | 2028 | 2029 | 2030 |
|---|---|---|---|---|---|
| OPS+ | 146 | 137 | 129 | 121 | 112 |
| WAR | 3.6 | 2.9 | 2.0 | 1.4 | 0.7 |
For context, and Alonso is currently beating the original year-one projection:
- ZiPS valued the five year contract near $110M against the $155M guarantee.
- FanGraphs’ Ben Clemens projected four years and $120M.
- The FanGraphs reader crowdsource averaged four years and $107M.
- A February 2026 ZiPS update raised the 2026 line to 4.1 WAR.
Where these figures come from
None of these were re-checked against the original releases. What this site can tell you is exactly how each one reached it, which is the difference between a figure you can go and check and a figure you have to take on trust.
- ZiPS valued the five year contract near $110M against the $155M guarantee.
- infographic-spec-v2.md section 5, citing the ZiPS projection FanGraphs published at signing in December 2025. Repeated here from the spec rather than re-checked against the FanGraphs release.
- FanGraphs’ Ben Clemens projected four years and $120M.
- infographic-spec-v2.md section 5, citing Ben Clemens at FanGraphs. Repeated from the spec rather than re-checked.
- The FanGraphs reader crowdsource averaged four years and $107M.
- infographic-spec-v2.md section 5, citing the FanGraphs reader crowdsource. Repeated from the spec rather than re-checked.
- A February 2026 ZiPS update raised the 2026 line to 4.1 WAR.
- infographic-spec-v2.md section 5, citing a February 2026 ZiPS update. Repeated from the spec rather than re-checked.
- The market cost of a win has historically grown by roughly 5 to 7 percent a year, which is why the dial defaults to 6.
- infographic-spec-v2.md section 5, which gives the range in a parenthesis without attribution. Like the base price below, nothing outside this project vouches for it.
- A win costs $8.5M in 2024, before the inflation the dial applies.
- infographic-spec-v2.md section 5, which gives it as a base price without attribution. Nothing outside this project vouches for it, and every dollar figure on the site is computed from it. It is the weakest-sourced number here and the most load-bearing.
The model
Three things move the odds between scenarios: how available he stays, what the six decline signals read, and where his production sits between the two comp groups. None of them changes what a scenario is worth. The cost of a win does that. Every formula is on The Formulas.
80% of 2026 is already played, so that season is anchored on what has actually been banked and only the remainder is projected. Later seasons stay projections, which is why three scenarios exist at all.
What each club should have paid
Orioles 2026-30$155M guaranteed · 5 yrs · ages 31-35
+$8.2M
Fair value $163.2M, so the club paid under it by $8.2M. It keeps the difference.
evidence supportsprice implies
That price implies 46% confidence in the Lasted pace. The evidence supports 56%, a gap of 10 points.
GradeFAIR VALUE
Mets offer (declined, 2023)$158M offered · 7 yrs · ages 29-35
+$62.7M
Fair value $220.7M, so the club offered under it by $62.7M. He signed elsewhere, so the club lost a player worth more than it was willing to bid.
evidence supportsprice sits past this scale
That price sits at or below what the deal is worth with no weight at all on the Lasted pace, so it needed no faith in that pace. The evidence supports 56%.
The bidUNDERBID BADLY
Both labels are bands on a continuous number, so read the dollar figure rather than the label: the figure moves with every reading and the label only moves when it crosses a cut point. The two vocabularies differ because the questions do: one club signed him and one was turned down, so the same gap means opposite things.
The assumptions
The dials need JavaScript. Everything above is the site's published position at its own assumptions: 162 games a year and 6% annual growth.
Availability shifts the odds between scenarios, never what one is worth. It opens where the log puts him. Durability lowers cliff risk but cannot erase it. Prince Fielder ran a 547-game streak, longer than Alonso’s, and two neck surgeries 26 months apart ended his career at 32.
Higher growth raises the value of later seasons, because a fixed salary buys wins in cheaper future dollars.
Scenario odds
Lasted pace56.0%
The pace of the hitters who aged well. 130+ wRC+ into the mid-30s.
ZiPS glide path41.0%
The projection published at signing. Drifting toward 1 WAR by 2030.
Early cliff3.0%
Strikeout creep or injury triggers a Howard or Abreu style drop.
The base column follows the ZiPS projection published at signing. The outer two are this site's own estimates from a small comp study, marked illustrative, and they are not projections anyone else has published. The odds above carry no such mark because all three are equally this site's own.
| Contract | Lasted paceillustrative | ZiPS glide pathpublished | Early cliffillustrative | fair value | gap |
|---|---|---|---|---|---|
| Orioles 2026-30 | $200.6M | $118.5M | $76.3M | $163.2M | +$8.2M |
| Mets offer (declined, 2023) | $260.3M | $173.6M | $125.3M | $220.7M | +$62.7M |
Three numbers for the same five years
This site gives three answers to one question, and put in the same unit they agree more closely than they have any right to. All three are wins across ages 31 to 35.
| Estimate | WAR | What it knows |
|---|---|---|
| ZiPS, as published | 10.6 | Written in December 2025 at signing. It knows nothing about the season being played or about any of the six signals, because both came after it. |
| What the valuation above implies | 15.5 | The scenarios on this page, anchored on production already banked this season and weighted 56/41/3 by the scorecard and the comp track. It never printed a wins figure; this is recovered from its own inputs. |
| What the comps imply | 15.6 | What 164 comparable hitters went on to produce from the same point in their own contract years, given a season like the one he is having. The middle half of them landed between 12.7 and 21.6. See the curves. |
They agree, and the way they stopped agreeing is worth the space. Earlier this method put the comp figure at 22.6 wins, seven clear of the valuation, by placing him on the average of the best 41 five-year runs in the pool. That was the wrong arithmetic rather than a bold call: those quarters are picked by how the five years turned out, so putting a hitter on them assumes you already know the answer, and no group of comparable hitters ever averaged that.
The figure above instead asks what happened to hitters from where he actually stands. A quarter of this contract has been played and its wins are counted, not guessed, so only the remaining years are projected, from what 164 hitters did after a season like his. The two estimates share no machinery: one is a scenario model anchored on production already banked, the other is a set of careers. Landing 0.1 apart is evidence rather than arithmetic.
For scale, the pool as a whole runs from 0.4 wins for the bottom quarter to 22.6 for the top. The fourteen the site used to reason from ran from 6.9 to 17, a narrower spread that turned out to understate both ends.
What the Mets got instead
Every figure above this line is the model’s. This one is not. Somebody has played first base in Queens all season, and what they hit is a matter of record.
| Player | G at 1B | PA | HR | AVG/OBP/SLG |
|---|---|---|---|---|
| Jared Young | 68 | 240 | 6 | .268/.321/.427 |
| Mark Vientos | 60 | 224 | 11 | .217/.250/.415 |
| Brett Baty | 16 | 64 | 2 | .186/.250/.305 |
| Eric Wagaman | 11 | 26 | 1 | .125/.192/.250 |
| Jorge Polanco | 2 | 10 | 0 | .200/.600/.200 |
| Luis Torrens | 2 | 2 | 0 | .000/.000/.000 |
| Gabriel Arias | 1 | 3 | 0 | .000/.000/.000 |
| Christopher Morel | 1 | 4 | 0 | .333/.500/.333 |
| All of them | 161 | 573 | 20 | .229/.283/.394 |
Through 133 team games to , with the club at 60-73. The bottom line adds the eight together rather than averaging their eight averages, which would weight three at bats like two hundred and twenty and give .166, a line nobody on this list hit. Games exceed the team’s total because more than one of them appeared at first in the same game.
Counted by game: a player who moved across to first in the seventh has that whole game’s plate appearances counted here, which is looser than a published positional split. Restricting it to games started at first gives .231/.283/.391, so the looseness moves nothing.
This sits beside the model and never inside it. Nothing here feeds the valuation, and it should not: fitting a fair value to the outcome it is meant to be judged against would make the judgement worthless.
MLB Stats API, queried 27 August 2026. For each player, the 2026 fielding game log gave the games he appeared at first base for the Mets (team 121, regular season only), and the hitting game log for exactly those games was summed. Not a published positional split: game-level rather than plate-appearance-level, which is stated on the page.
Alonso's side of the ledger
The team-side numbers above are only half of it. By declining seven years and $158M in 2023, Alonso earned $20.5M in 2024, $30M in 2025, and $155M across 2026 to 2030.
$205.5M over the same seven years, +$47.5M for betting on himself.
A contract can be a poor deal for the team and an excellent one for the player. Both readings on this page are true at once.
What is not in the number
The cost of a win is derived by dividing real contracts by real WAR, so it already contains everything the market prices on average. Anything added on top has to be specific to one club, or it is being charged for twice.
- Postseason leverage, modelled
- The same wins are worth more to a club near the cut line. Scored as a deviation from a typical signing club, because clubs that sign free agents are mostly contenders and that leverage is already in the market rate. Correctly differenced it is a small term, usually negative.
- Merchandise, not modelled
- MLB licensing royalties go to a central fund split equally across all thirty clubs. A club selling more of one player's jerseys captures roughly a thirtieth of the extra royalty. Team-specific merchandise value is close to zero, which is the opposite of what most people assume.
- Gate and attendance, not modelled
- Real and club-specific, but small and badly confounded with team quality. No honest figure separates the player from the winning.
- Local media and sponsorship, not modelled
- Regional deal terms are not public. There is no estimate to make, so none is made.
A site whose whole claim is publishing its formulas gets more credit for naming what it refuses to estimate than for inventing a merchandise number.
What these terms mean
- OPS+
- An older park-and-era-adjusted measure of a hitter, built from how often he reaches base and how much power he shows. 100 is average.
- WAR
- One number for a player’s whole season, counting hitting, fielding and how often he played, expressed as games his team won that a freely available replacement would have lost.
- $/WAR
- What one win costs on the open market in a given year. It is the conversion this site uses to turn projected production into dollars, and it is the number the inflation dial moves.
The formulas behind them are on The Formulas.
Production value is the year-by-year WAR path multiplied by the cost of a win, starting at $8.5M in 2024 and compounding at the chosen rate. That base price is the least sourced figure on this site and everything in dollars depends on it; see where these figures come from. The base case is the ZiPS projection published at signing. The Lasted pace and the early cliff are comp-study estimates around it and are not projections in the same sense. Fair value is the guarantee at which a club breaks even.