Manuel Balce Ceneta/Associated Press

In all likelihood, the richest contract in Major League Baseball history will soon belong to a player whose downside is as perilous as his upside is extraordinary.

To the extent that there ever was a secret, the secret is out that superstar outfielder Bryce Harper and super-agent Scott Boras are indeed looking for a record deal in free agency.

According to Chelsea Janes of the Washington Post, Harper could have accepted a 10-year, $300 million offer from the Washington Nationals in September. But as far as Boras is concerned, such a deal wasn't close to good enough.

"They did not pay anywhere near [Harper's] $400 million to $500 million in [true value]," Boras told Joel Sherman of the New York Post. "This has been great value and is great value."

The chances Harper will pull in $500 million—and thereby beat Giancarlo Stanton's record $325 million deal by $175 million—are remote, at best.

It is nonetheless expected that the 26-year-old's next pact will indeed raise the bar for professional athlete paydays. MLB Trade Rumors, for example, projects a 14-year, $420 million contract. Even a more conservative projection from Fancred's Jon Heyman still puts him at $330 million over 11 years.

Split the difference, and something in the realm of $350 million seems in order. Certainly, whoever pays up will be most excited about Harper's potential.

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This is, after all, a player who's largely lived up to being a Sports Illustrated cover athlete at 16 and a No. 1 draft choice at 17. Harper won the National League Rookie of the Year as a 19-year-old in 2012. He was the NL's unanimous MVP three years later. There's been only one season out of his seven in which he wasn't an All-Star.

The numbers are there, too. Harper is one of only six hitters to make over 3,000 plate appearances and put up a .900 OPS since 2012. His 184 career home runs are the 12th-most for a player through his age-25 season.

More specifically, his 2015 efforts (1.109 OPS and 42 home runs) proved he can be baseball's best in a given year. Albeit in a losing cause, he showed he can take over a playoff series with a monstrous NLDS outburst (1.251 OPS and three homers) against the San Francisco Giants a year earlier.

To boot, Harper's appeal goes beyond the diamond. As of 2016, his Q score rated him as the most recognizable active MLB player—over fellow young superstars Mike Trout and Kris Bryant. Their Google traffic sends a similar message:

Teams in the Harper sweepstakes can look at him and see a tantalizing package of youth, talent and marketability. In other words: precisely the kind of person who could justify the biggest investment ever made in a professional baseball player.

And yet, such an investment could just as easily become a massive bust.

The most relevant comparison for what Harper represents is what Alex Rodriguez was in the 2000-2001 offseason. He was a young, charismatic, MVP-level talent for sale to the highest bidder. Enter the Texas Rangers with a groundbreaking 10-year, $252 million contract. Adjusted for inflation, that pact would be worth roughly $360 million today.

On some levels, it's reasonable Harper should get the modern equivalent of A-Rod's contract. Harper is a year older now than A-Rod was then, but his profile is similar, and even some of their numbers look alike.

However, the comparison breaks down once wins above replacement—which captures a player's total hitting, baserunning and defensive value—is factored in. Per Baseball Reference:

The peaks (2015 for Harper, 2000 for Rodriguez) are similar, but the consistency is not. Rodriguez shook off a slow start to become a dependable star in his final five seasons with the Seattle Mariners. For his part, Harper has been a downright bad player in three of the last five years.

Rodriguez's early track record isn't the only one that can make Harper's look unspectacular. Strictly among active players, those who've accumulated more WAR through their age-25 seasons include Trout (54.2), Mookie Betts (35.2), Jason Heyward (29.8) and, yes, fellow superstar free agent Manny Machado (33.8).

Injuries haven't helped Harper's cause. He was afflicted by knee problems in 2013 and 2017, as well as by a thumb malady in 2014 and, per Sports Illustrated's Tom Verducci, a bum shoulder in 2016. That's more than enough for an "injury-prone" label and should concern prospective suitors.

Beyond that, how much Harper will give outside the batter's box is debatable. Though he's an outstanding athlete, his baserunning and defense can be charitably described as unpredictable. As Jeff Sullivan covered at FanGraphs, the latter was outright terrible in 2018.

Even Harper's bat has red flags. His offensive productivity has tended to fluctuate wildly between outstanding highs and pitiful lows, and not just because of injuries. There are times Harper loses his approach, and he's not as efficient a slugger as he should be.

A hitter like Harper, who doesn't see many pitches in the strike zone, ought to choose his swings carefully and frequently make hard contact when he does let loose.

He does exactly that when he's hot. But from an overall perspective, he's no Trout:

Data courtesy of FanGraphs

For all the reasons referenced, none of the red flags will, or should, bar Harper from a record-setting payday. To throw one more on the pile: Per MLB.com's Andrew Simon, the historical comparisons for both Harper and Machado bode well for their futures.

There is nonetheless an all-too-obvious disparity between what Harper can be and what he is. His celebrity and accolades make him look like a singularly talented superstar slugger. In actuality, he's a part-time superstar whose talent for slugging isn't really that singular.

Which is to say that nobody has any real clue what will become of the megacontract he'll soon sign. There are probably 50-50 odds it'll be money well spent or money down the drain for his new employer.

To both, "godspeed" will be the only thing to say.

Stats courtesy of Baseball Reference and FanGraphs.