Here's a certainty to place alongside death and taxes: Manny Machado and Bryce Harper are going to sign massive contracts next winter.
Oh, sure, they could sign massive contracts before next winter if their current respective teams—the Baltimore Orioles and Washington Nationals—manage to lock them into extensions.
Who are we kidding, though? Two of the game's brightest young stars are going to test the market after the 2018 season. When they do, the deals will be gargantuan.
The only questions: How gargantuan, and which player will get more moola?
Let's begin with some fast facts. Machado will turn 26 in July. Harper will reach the same age in October. Hard as it is to believe, both are just coming into their primes.
In six big league seasons, Machado has made three All-Star teams, enjoyed three top-10 and two top-five American League MVP finishes, and compiled 26 fWAR. His peak season by fWAR came in 2015 when he posted a mark of 6.9.
Harper, too, has spent six seasons in the big leagues. He's made five All-Star appearances and won Rookie of the Year and a National League MVP Award. Harper's total fWAR (27.7) and peak fWAR season (9.5 in 2015) both edge Machado.
The parallels are striking.
On the durability front, Harper has battled a range of injuries and eclipsed 150 games only once in his career. Last season, he was limited to 111 games by a knee injury.
Machado has twice undergone season-ending knee surgery, once on each knee, and played only 82 games in 2014. Since then, however, he's played 162 games in 2015, 157 games in 2016 and 156 games in 2017, putting health concerns to rest.
Defensively, Harper has put up 28 defensive runs saved and a 19.9 Ultimate Zone Rating in the outfield. He's had years, however, where the defensive metrics rated him negatively.
Machado, on the other hand, has gotten consistently glowing marks, amassing 81 DRS and a 66.5 UZR for his play at third base. The Orioles recently announced Machado will play shortstop full-time this season, a move that should only boost his appeal to potential suitors who could eye him for either position.
So what kind of deals will Harper and Machado be looking at next winter? In December 2016, USA Today's Bob Nightengale reported Harper was seeking something in the neighborhood of 10 years and $400 million.
Fox Sports' Ken Rosenthal also mentioned the $400 million figure in connection with Machado (via ESPN.com's Kyle Brasseur).
Baseball has never seen a contract in excess of $400 million before, though Giancarlo Stanton cracked the $300 million mark in November 2014.
It's tempting to be bearish on whether either Machado or Harper can get to $400 million considering how stingy MLB shoppers have been this winter. With pitchers and catchers set to report Feb. 13, a whole gaggle of top free agents remain unsigned, and even the glitziest names may have to settle for fewer years and dollars then they'd hoped.
That said, a lot of these teams could well be saving up to make a run at Harper, Machado or another member of the vaunted 2018-19 free-agent class. And the luxury tax threshold—which many traditionally big spenders are trying to stay under—is set to rise from $197 million in 2018 to $206 million in 2019 and $210 million by 2021.
It's entirely conceivable both Harper and Machado could get $400 million deals that lock them up into their mid-30s.
To the second question: Who will get more? It's a tough call, and it should be close.
Machado has been the healthier, more consistent player in recent years. He's better defensively and can man a premium position.
Harper's ceiling, however, is probably a bit higher. Good as he's been, Machado has never had a campaign like Harper's 2015, when the Nats outfielder clubbed 42 home runs and led the game with a .460 on-base percentage and 1.109 OPS. That's treading into early 2000s Barry Bonds territory.
Harper and Machado are both charismatic figures, but Harper's brash personality and "make baseball fun again" antics make him arguably MLB's most marketable star.
We'll give a slight edge to Harper in terms of contract size, though the years should be the same for both players, likely with opt-outs built in.
Here's what's certain: Baseball's firmament is going to shift next winter along with its balance of power. When that happens, two young men with strikingly similar career trajectories are going to get filthy stinking rich.
All statistics courtesy of FanGraphs.