The biggest reliever contract in baseball history was handed to Jonathan Papelbon in 2012 when the right-hander received four years and $50 million from the Phillies. The biggest yearly salary ever recorded by a reliever remains Mariano Rivera‘s $15 million figure from both 2011 and 2012. This year, both of those records will surely fall.

After all, we’ve just concluded a postseason in which starters pitched the fewest innings per start in playoff history. And a reliever won the American League Championship Series MVP award. And relievers, in general, receive much more per win than players at any other position. Against that backdrop, this offseason features two elite free agents in Aroldis Chapman and Kenley Jansen — only a year after Darren O’Day was the best reliever available in November.

It’s a combination of forces that makes you wonder how high the price might go for their services. But before we start predicting nine-digit contracts for either of these closers, we also have to remember that a deal like that would represent a doubling of the previous high.

The simplest way to look at the issue is to put relievers in their own bucket — to basically ignore the rest of baseball — and look at the previous contracts for guidance when it comes to Chapman and Jansen. The idea might be that finding a reliever that is able to repeat his performance year to year is scarce, and then that “reliever wins” may have their own pay structure. So let’s look at the highest paid relievers and their projected performance going into the contracts they signed.

Highest Paid Relievers With Contract Details
Contract Overall AAV AAV $16 NPV $16 Age 3yr WAR 3yr WPA
Billy Wagner 06-09 $43 $11 $18 $59 35 5.9 9.6
B.J. Ryan 06-10 $47 $9 $16 $64 30 7.5 5.7
Joe Nathan 08-11 $47 $12 $18 $59 33 7.7 11.3
Brad Lidge 09-11 $38 $12 $17 $44 32 4.2 5.5
Francisco Rodriguez 09-11 $37 $12 $17 $45 27 5.8 11.4
Mariano Rivera 11-12 $30 $15 $20 $34 41 6.9 10.2
Rafael Soriano 11-13 $35 $12 $15 $38 31 4.0 5.9
Jon Papelbon 12-16 $63 $13 $16 $62 31 5.7 9.2
Rafael Soriano 13-14 $28 $14 $16 $23 33 3.4 7.9
David Robertson 15-18 $46 $11 $13 $41 29 4.9 6.0
Andrew Miller 15-18 $36 $9 $10 $32 29 3.1 2.8
Darren O’Day 16-19 $31 $8 $8 $25 33 3.4 5.8
Aroldis Chapman 2017-? 29 8.0 7.9
Kenley Jansen 2017-? 29 7.0 5.4
AAV = average annual value with bonuses and deferrals and buyouts included
AAV $16 = AAV in today’s dollars
NPV $16 = net present value in 2016 dollars considering deferments
3-year WAR and WPA = sums of wins and win probability added going into contract year

The first thing you might notice is that these things are fairly rare. And the last time two pitchers this good were on the market at the same time was when Mariano Rivera and Rafael Soriano were out there at the same time — briefly — before the 2011 season. Or when Andrew Miller and David Robertson were available going into the 2015 season, maybe. As much as the big deals don’t really match up with the WAR-based prices, the rarity of the big-reliever deal seems to suggest that there is some reticence when it comes to throwing too many zeros at a short-inning pitcher.

Because of the rarity of these types of signings, it’s hard to say there are any real trends. Can we say that Darren O’Day’s contract, in tandem with Miller’s, suggests that teams are trying to spend less on less well established, but still great, late-inning relievers instead of handing cash to “proven” closers? That might be wishful thinking. We didn’t put Craig Kimbrel on here because his arbitration years were bought out, but he got plenty of money, too. And maybe it was just that there weren’t a lot of relievers who hit the market and were worth the money.

Chapman and Jansen stand out here. Chapman has the most WAR among this group of elite relievers headed into his free-agent season — and both Chapman and Jansen are on the younger side of the pitchers in this sample. Only Francisco Rodriguez was younger, really.

Once you convert yesterday’s average annual values into today’s prices, it looks like you reach an asymptote. Only the legendary Rivera ever received $20 million a season — on a short contract, remember — even as the others got pretty close. The laws of inflation alone suggest that $20 million a year wouldn’t be a crazy number for either one of these pitchers.

When it comes to length… we’ve had some five-year deals, but did they work out well? B.J. Ryan‘s tenure with the Blue Jays (and ultimately in the majors) was ended 3.5 years into a five-year deal after the reliever put up one strong season, a second okay one, and 1.5 injured years. And Ryan was really good going into that contract, featuring the third-best WAR total on the board above.

The Papelbon deal was actually signed as a four-year deal with an option. That option vested with his trade, so I presented it that way above. But if our goal here is to consider the possibility of a five-year deal for either Chapman or Jansen, Papelbon’s doesn’t officially count as precedent. Still, he was under contract for five years and managed to finish the deal. He produced five wins for the $63 million he was paid.

Still, our ideas of reliever valuation might be evolving a bit. We’re at least considering that perhaps win probability added (WPA) might be a good way to look at the “did he do it or did he not?” aspect of an endgame pitcher. Sky Kalkman took a shot at it — and though I wouldn’t use the numbers for starters (Tom Tango made a good case against it) — I find this takeaway interesting:

Given the brevity of Twitter, the wording is a bit dense, but basically here’s Kalkman’s point: the very best closers might be worth another win if we added in WPA runs into their metric. That’s probably only true as long as they remain as good as the top three closers in the game, but every win counts. A couple wins on Papelbon’s ledger, and he cost less than $10 million a win.

That still seems like a bad deal, perhaps — even now, years later, estimates for the price of a win still haven’t hit $10 million — but then you have to return to this list. If you want to buy a great late-game reliever, you’re looking at one or two or three guys every year. You can’t buy a backup catcher and make him a closer — unless you get lucky with Christian Bethancourt as the next Jansen — and even if you could, you wouldn’t know for sure that you could going into the season, and the dollar premium is there for that reason.

In terms of overall value on your roster it might still be better to buy Dan Hudson and some other pieces than spend $100 million on five years of Aroldis Chapman, but the latter choice isn’t crazy in the context of yesterday’s reliever contracts. Of course, the only reliever who actually got $20 million a year in present-day was a Hall of Fame closer and past five-year deals haven’t worked out so well… which seems to suggest that a five-year deal at $20 million is unlikely. But those are just facts. What are facts in the face of a bidding war between teams that projected to qualify for the 2017 playoffs?

Those teams will need one more stud reliever to make their teams hum in October, and some of them will be left without a seat when the music ends. That scarcity is why a reliever contract for five years and $100 million is a strong possibility this offseason.