Several days ago, in these pages, I discussed the the merits of a contract extension for Max Scherzer. When push came to shove, I advised against such a deal based on how rare it is for a pitcher to produce past age 33. The Tigers have a collection of decisions coming over the next couple of seasons, but the other big one concerns the future of Miguel Cabrera. Should the Tigers look to lock him up long term?

Let’s settle some particulars right off the bat. Cabrera is under control for the next two seasons at $22 million per season which covers his age 31 and age 32 season. Cabrera is an elite bat who rarely misses time, but offers very little value (and often negative value) on the bases or in the field. If he walked away from baseball today, he’d be a borderline Hall of Famer. The only knock would be longevity, so as long as he hangs around and is reasonably productive for another couple of years, you’re looking at one of the better players in the game’s history. Certainly one of the better hitters.

But Cabrera’s coming contract isn’t about who he was, it’s about who we think he’s going to be. Let’s approach this from two angles. We have to consider what Cabrera will ask for and what the Tigers should pay. The big question will be the length of the deal, which is a little hard to gauge this far out from free agency. Let’s assume that adding an extra six years onto the current deal will be a satisfying length. That would take Cabrera through age 38. Let’s also assume that Cabrera won’t take a pay cut. So at the very least, this extension will run 6 years, $132 million. But that’s a floor, not any sort of likely number. We have a sense that the price of a win is about $6-$7 million on the free agent market and that two years from now it will at least be as high as it is now. If we work from there, we can imagine Cabrera putting up something like 23 wins over six seasons if we’re aging him in a standard fashion. At that rate, we’re talking about $140 million to $161 million in terms of value. The bottom end is only $23M per season and the top end is closer to $27M. Let’s call it $28 million a season for 6 years. $170 million.

That’s less than Felix, Verlander, Pujols, A-Rod, and Cano – but that makes some sense. Pitcher contracts aren’t really comparable and he’ll be older than the pitchers at the time of the deal. The Pujols deal is a pretty good place to start. Pujols was 32 entering his 10/$240M deal. And Pujols had about 83 fWAR at the time. Cabrera will have something like 66 fWAR. Cabrera is great, but Cabrera isn’t Pujols. Cabrera will get a higher AAV at $28 million, but for fewer years because teams recognize that those really long deals are kind of silly. And remember, we’re talking about an extension. So the total value is 8 years and $214 million. Cano just got 10/240 as a free agent, while younger, and while being a far superior defender. Pujols got the same as a free agent, while the same age, and while being better in the preceding seasons. That makes some sense to me.

So 6/170 seems like a decent place to start. Maybe money keeps flowing and things accelerate. Maybe it’s 6/180. That would make him the highest paid player per season in baseball. I wouldn’t think he’ll continue to be a top five player that far into the future, but he’s right around that group at the moment, so we’re in the ballpark.

So, should the Tigers pay up? Let’s work backwards. A $180 million deal assumes something like 26 to 30 wins above replacement from 2016-2021 or ages 33-38. Let’s be generous and call it 25 wins, factoring in some inflation and various other nonsense. Can Cabrera be worth 25 wins over those six seasons? We’re pretty confident he’ll provide surplus value in 2014-2015, and that his first extension will be an excellent deal when all is said and done, but is it worth making a longer commitment to centerpiece of the Tigers current offense?

25 wins over six years assumes an average of about 4.2 per season. Let’s look at this a few different ways. First, how common is it for a position player to earn 25 WAR from ages 33-38? It’s happened 27 times in MLB history, which you can peruse here. But let’s get a little more specific. Let’s try since 1969. Nine names.

1. Barry Bonds
2. Mike Schmidt
3. Edgar Martinez
4. Pete Rose
5. Ozzie Smith
6. Chipper Jones
7. Rafael Palmeiro
8. Frank Robinson
9. Mark McGwire

That’s a nice list, for sure, but Ozzie Smith’s value is all defense, so that’s a silly comp. Let’s be generous and call it 8 guys out of 209 to have 2000 PA since 1969 between ages 33-38. That total number is going to be a little off based on guys who are still inside the age window, but you get the idea. The odds of getting 2000 plate appearances is low. Then the odds of being great is lower still.

An important factor is Cabrera’s defensive value and how long before he can move to DH – but that isn’t really true. The difference in the positional adjustment is only five runs from 1B to DH, which means that unless Cabrera ends up being a very good defender at first, it’s probably not a huge difference. Let’s call it two years of 1B and four at DH. Let’s call him a league average defender at first, which is probably generous more than it’s underselling. We’re talking about something like -120 runs between position and defense. Let’s assume he keeps playing 140+ games or so and is an average baserunner (which is surely won’t be). That’s +60 runs before we get to offense. He needs to get to about 235 total for us to get to 25 wins. That’s 175 offensive runs over six years. That’s about 30 a year. That’s doable, but not easy.

If he averages about 650 PA, that means he’ll need to average roughly the 2013 equivalent of a .374 wOBA adjusted for changes in the future run environment. At his peak, that has been no problem. But in his mid-thirties, it’s up in the air.

Let’s try one more quick thing before getting to the point. Let’s try players since 1969 ages 28-30 with at least 1000 PA and let’s find some comparable players to Miguel Cabrera. He ranks 11th on that list in terms of fWAR. Of the top 30 on that list, let’s find those players with -20 runs or worse of positional and fielding value during the same period. It’s a short list. Cabrera, Giambi, and Helton. It’s rare for a player to be this good at ages 28-30 without much defensive value. In theory, we’d expect elite bat only players to fall harder because they can’t make up the value elsewhere. For what it’s worth, neither Giambi or Helton were worth even 10 WAR from 33-38.

It’s hard to find a good comparison for Cabrera in history. You can find his bat and you can find his glove, but you can’t find the whole package as one. If we think he ages well enough, he can earn a 6/180 deal, but you don’t love what history suggests about the odds. You’re betting on Cabrera being a bit of an outlier, which isn’t a terrible bet given his history to date, but that circles us back to the point I’ve made several times on Twitter and will leave you with here.

I can envision a world in which Cabrera is a fair value at 6 years and $180 million. It’s not a ridiculous idea. But I’m waiting to offer an extension for a simple reason. He’s not going to get better. 2013 was his peak. I’m confident about that, and that’s without worrying about his recent injuries and his body type. He’s never going to get better, only worse. I don’t think it’s going to happen super fast, but you can’t fight father time (legally!). A standard aging curve sets him up for 6/180 or so being a fine deal, but I’m going to bet he ages just a little bit worse. I’m going to wait and see if you can get him for cheaper in a year or two. Maybe in two years he’s still a superstar and you have no problem paying the extra few million because you waited. That’s the cost of doing business. But maybe Cabrera is just a run of the mill all-star at that point and you can save yourself several million. Or maybe you won’t want him at all. I think the risk of signing him now outweighs the discount you get from locking him up early.

Put it this way, I’m not in a rush. If Cabrera maintains his value over the next two seasons, you live with the consequences. If he doesn’t, you pocket the difference. I’m willing to make that bet when you already know that you have two more seasons of Cabrera at an excellent value. There’s no reason to roll the dice until you need to. Don’t panic and extend him, wait and see if you still want to when the hour is actually near. I can see a world in which extending him makes sense, but I’m also willing to wait before making the final decision.