Last July, LeBron James congratulated Steph Curry on landing a five-year, $200 million deal with the Golden State Warriors. It was one of the richest contracts in American sports history, but James made it clear he thought Curry was still underpaid.

So tell me again why there's a cap on how much a player should get?? Don't answer that. Steph should be getting 400M this summer 5yrs. #JMTs https://t.co/jMYfI0umWK — LeBron James (@KingJames) July 1, 2017

James tweeted that in reference to a report that the Warriors had more than quintupled in value since Curry's arrival to the team. It reopened an old topic: Just how much would James be worth in an open market in which there was no NBA salary cap or maximum salary rule?

Over the years, as James has occasionally referenced being underpaid -- "At the end of the day, I don't think my value on the floor can really be compensated for because of the [rules]," he said in 2013 -- there have been varying attempts by economists and journalists to try to quantify his true worth.

Well, there may finally be a comparable athlete who sets James' true market value.

On Tuesday, European soccer star Cristiano Ronaldo agreed to a new contract with Juventus. Not including the transfer fee to Ronaldo's former team, Real Madrid, that will exceed $100 million, Ronaldo will get a four-year contract worth about $258 million, or an average salary of $64.5 million per season.

Give or take a few million a year, that massive annual figure could indeed be what James might fetch in an uncapped NBA market.

James and Ronaldo are quite similar. Both are icons of their sport and worldwide marketing superstars with tens of millions of followers on social media. Both are 33 years old. James turned pro at age 18, Ronaldo at age 17. Both have won a slate of player of the year trophies, hold numerous scoring records and have claimed conference and league championships.

And both just signed four-year contracts. Ronaldo landed with the Italian soccer powerhouse that is one of the richest and most storied sports franchises in the world, valued at $1.47 billion by Forbes. James joined the Los Angeles Lakers, the NBA's richest and most high-profile franchise, valued at more than $3 billion by Forbes.

But James will be getting about 40 percent less per year than Ronaldo, earning $153 million for an average salary of $38.3 million.

LeBron James vs. Cristiano Ronaldo James Ronaldo Age 33 33 Joining Team # 3<< 4 AAV Contract $38.3M $64.5M League Titles 3 5 National Team Titles<<< 3 1 MVP/Ballon d'Or 4 5 All-Star/FIFPro XI 14 11 Seasons as pro 15 16 Age at first pro season 18 17 >>Cavaliers: 2x >>>Olympics/EURO Championship

To compare, Michael Jordan signed his largest contract at age 34, which both James and Ronaldo will turn next season. Jordan's deal was before the NBA instituted max contracts, and the Bulls paid him $33 million in 1997-98. When adjusted for inflation, that deal comes out to $52 million. Now, 20 years later, Ronaldo has passed that mark. James has not.

Juventus and the Lakers are in the top 1 percent of revenue generators in all of sports. For the 2016-17 season, the Lakers had revenues of $339.5 million, according to league sources. Juventus, a publicly traded team, pulled in $451.7 million, according to its financial documents.

There are some key differences in how much gets to the bottom line, though. The Lakers have to share in what can be described as a socialistic system aimed to achieve better parity between the haves and have-nots in the NBA. Juventus doesn't have to share as much.

For the 2016-17 season, for example, the Lakers gave $49 million to other teams in revenue sharing. The Lakers received an equal share as their 29 other partners in television money, which won't change regardless of how many times they're on national television with James. Though the Lakers will likely see a boost in local merchandise sales, much of the revenue generated by James' new jersey sales will go into a leaguewide pool that is also shared with players.

The opposite is true for Juventus. Fifty percent of the Serie A media rights is split evenly among all 20 teams, 30 percent of the money is split based on results and the rest is determined by other factors that typically benefit Juventus.

Juventus also keeps the roughly $20 million a year it gets from its jersey sponsor, Jeep. The Lakers scored a three-year jersey patch sponsorship with Wish last season that pays the team roughly $13 million per year. Of that $13 million, the Lakers wind up with $3.25 million, another $3.25 million goes to revenue sharing and the other 50 percent ($6.5 million) goes to the players.

James once joked that he'd be willing to play in Europe if he could get paid $50 million per season. If he ever wants to get to that number, he may want to take up soccer.