By Cliff Corcoran

Saturday's news of Bryce Harper and the Washington Nationals coming to terms on a record one-year salary for an arbitration-eligible player ($21.625 million for 2018) wasn't quite the big contract announcement we've all been anticipating. But the question is posed anew: Just how ridiculous is Harper's eventual free agent contract going to be?

We know the touchstones. Giancarlo Stanton's 13-year, $325 million extension with the Marlins holds the record for most total value. Zack Greinke's six-year deal with the Diamondbacks holds the record for average annual value at $34.417 million. Harper's current teammate, defending National League Cy Young Award winner Max Scherzer has three $35 million salaries written into his contract, though all three are deferred over a seven-year span. We expect Harper to surpass them all. Indeed, last December USA Today's Bob Nightengale reported that one "high-ranking Nationals executive" told him that Harper was seeking "at least" a 10-year, $400 million deal.

At that time, coming off yet another disappointing and (allegedly) injury-plagued season, those demands seemed absurd. Three of Harper's past four seasons were undermined by injury, and in both 2014 and 2016, he fell short of the value of a league-average regular, compiling just 2.6 wins above replacement in those two seasons combined.

This year, however, Harper has not only rediscovered his 2015 MVP form, but has thus far surpassed it. Just as importantly, despite a brief absence due to a sore groin earlier this month, he has thus far managed to stay healthy and tremendously productive beyond his typically excellent April. Harper's hot start (.384/.500/.742 with 12 home runs and a 224 OPS+ entering Tuesday's action) has surely played a role in the Nationals handing him a record salary for his final arbitration-eligible season, and those two things have once again stoked the flames of anticipation over his potential free-agent earnings.

Consider how the past six weeks have changed Harper's projection. Back at SI.com, I used a formula, created by Jay Jaffe, to determine the actual dollar value of free agents based on their projected production and the dollar value of a marginal win (that is, one win above replacement level), adjusted for inflation over the life of the contract. It's a blunt system based on bWAR projections that sometimes reached as far as ten years into the future. However, it treated all players equally in terms of rate and age of decline, and not only served as a good point of comparison, but produced results similar in scale to the contracts those players eventually signed, often suggesting smaller contracts than the players wound up with.

The starting point for the bWAR projections in that system is a 5/4/3 weighted average of the player's previous three seasons that calculates their most recent season five times, their penultimate season four times, and their third-most-recent season three times. If we do that with Harper's 2014 to 2016 seasons (1.0, 10.1, and 1.6 bWAR, respectively), we get a 4.28 bWAR projection for his next campaign. However, if we pro-rate Harper's hot start and use his 2015 to 2017 seasons (10.1, 1.6, and 10.5 bWAR, respectively) we get a 7.43 bWAR projection for 2018. If we then assume that Harper will maintain that level of production through his age-27 season (typical peak age), then shed 0.5 bWAR per season thereafter (the standard rate of attrition for hitters used by the system), we can see just how much his earning potential has recovered in the last six weeks.

Using the 4.28 bWAR figure, Harper would project to be worth $234.82 million in his first 10 post-free-agency seasons before his decline brought him close to replacement level at the age of 35. That contract, with its average annual value just shy of $23.5 million, likely represents the floor of Harper's potential earnings, yet would still stand as the seventh-largest contract in Major League history and top the total value of the contracts signed by previous arbitration record holders David Price ($217 million), Prince Fielder ($214 million), and Scherzer ($210 million).

Here comes the fun part. Using the 7.43 bWAR projection, Harper would be worth a whopping $560 million over those ten seasons, and if he wanted to match Stanton in terms of years, he could motivate a 13-year, $664 million deal, which more than doubles the total value of Stanton's record contract.

I'm not saying there's a team out there that could afford that, or that any team would even be willing to break the record by that much if it could. What I am saying is that, if Harper can prove that 2015 was more than just an isolated case of everything going right for one season for a talented but injury-prone player, the projections would justify a contract of that size. In MLB's economy, his on-field production would be worth that much.

While you pick your jaw up off the floor, there are two key factors, beyond Harper's performance potential, that are driving those figures. The first is his age. Harper will be 26 in his first free agent season, still just entering his expected prime. My calculations start his decline in his third free agent season at the age of 28, but he could easily sustain his peak longer than that (of course, he could also decline faster once his skills start to diminish, offsetting that longer peak). The second is the inflation of the cost of a win. Per an estimate by ESPN's projection expert Dan Szymborski, the value of a marginal win in 2017 is $7.25 million. Szymborski's estimates in recent years have tracked closely with the 5.4 percent annual inflation built into Jaffe's system. If we continue that trend, by the tenth year of Harper's free agent contract, a single marginal will be worth nearly $13 million, double its value in 2015. Combine the rising value of a win, and Harper's lack of near-term decline, and you get a player who, via this optimistic projection, will be worth more than $60 million per year in his age-27 to -29 seasons, and still worth more than $40 million per season in his mid-thirties.

Want to really break the system? Let's say the 2015 and early '17 versions of Harper are the real deal, he puts the injuries behind him and becomes the left-handed version of Mike Trout in terms of annual value. Trout has averaged 9.5 bWAR over the past five seasons. If we start Harper's projection at that level, he would be worth $773.6 million in his first ten free-agent seasons and could earn out a $966.9 million contract over 13 years. Throw in a fourteenth year, his age-39 season, and we're literally talking about a billion-dollar player.

That brings up the question of just how long Harper's next contract will be. If he signs for ten years, he would hit free agency again after his age-35 season. That's not ideal, particularly in the scenario that has him declining to replacement level at that age. He'd be better off singing a shorter deal to take a double-dip of free agency, or going whole hog and signing away the rest of his career. His performance over the remainder of this season and next could be the determining factor there. If he plays at an MVP level both seasons, he should get every year and dollar he can. If the injuries return and doubt seeps back into the minds of prospective buyers, he should aim for that second chance. Most likely, Harper will have an opt-out clause in his new contract, regardless of the length (Stanton does, though he'd be a fool to use it), but length is obviously a key factor in the total value of the deal.

It will also be interesting to see how Harper's contract is impacted by an often-overlooked outside factor. Harper is not the only 24-year-old superstar who will reach free agency after the 2018 season. Orioles third baseman Manny Machado is just three months older than Harper and could motivate a $400 million deal of his own. Even with his relatively slow start, Machado projects to be a five-win player in 2017 and a six-win player annually going forward. Putting that figure into the system (6.1 bWAR to be exact), Machado projects to be worth $449 million over his first ten free-agent seasons. If there's a team out there willing to pay Machado what he's worth, it could reset the market for Harper. On the other hand, there may not be two teams willing to break the $400 million mark (or one willing to exceed $900 million for two players). If not, one of those players might have to settle for far less than his actual value. Coming into this season, it was still an open question as to which player would be the better buy come the fall of 2018, with things looking more favorable for Machado. However, if Harper can stay healthy and prove his 2015 wasn't a fluke, that question will have an easy answer.

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Cliff Corcoran is a Sports on Earth contributor and a regular guest analyst on the MLB Network. An editor or contributor to 13 books about baseball, including seven Baseball Prospectus annuals, he spent the last 10 seasons covering baseball for SI.com and has also written for USA Today and SB Nation, among others.