How much is the best defender in the world worth? Unfortunately, we’re about to find out.

Early on in Saturday’s Merseyside Derby, Everton keeper Jordan Pickford seemed to briefly lose total control of not only his body but also his ability to perceive time and space. The result: a knee injury for Liverpool’s Virgil Van Dijk. And despite just the vague confirmation from Liverpool -- a “knee injury” with “no specific timescale .. being placed upon his return” -- it seems likely that the 29-year-old VVD will miss the rest of the season, if not an even longer stretch than that.

The story of VVD at Liverpool can be told pretty simply: A colossal, preternaturally calm center back arrives at Anfield for a world-record fee halfway through the 2017-18 season. Almost immediately, a weak, preternaturally frantic defense becomes one of the world’s best and pulls the rest of the club along with it. In VVD’s first half-season with the club, Liverpool made the Champions League final. In his first full season with the club, Liverpool posted the third-most points in Premier League history and won the Champions League. In his second full season with the club, Liverpool posted the second-most points in Premier League history and won the Premier League. Doesn’t get much better than that.

It’s impossible to disentangle VVD from Liverpool’s success because he’s always on the field -- almost literally. In his first two full Premier League seasons with Liverpool, Van Dijk played 6,805 minutes. In other words, he played every possible minute save for 35, when he was subbed off in the 55th minute of a 3-0 win over Southampton in September of 2018. “It’s not cool but should not be too serious,” Jurgen Klopp said at the time. Still not cool, and now it is serious, too.

The injury is awful, not only because of the freak, accidental nature, but because Van Dijk is a fantastic soccer player at the tail end of his prime in a profession where your career is typically over before you turn 40. He might miss the Euros this summer for the Netherlands, and who knows if he’ll ever be the same player again. The older you get, the harder it is to bounce back from something this serious. Whatever color glasses you’re wearing while reading this, I think we can all agree that we hope we get to see the old VVD again, but there’s no guarantee we ever will.

And without their ever-present lodestar still leading the way, might Liverpool never be the same, either? It all depends on one thing: just how big of an impact can one defender can make?

Let’s start with the betting market, which remains the most-likely-to-be-accurate reflection of what will happen on a soccer field. Before the game against Everton, Sporting Index projected Liverpool to finish on 85 points -- down one from their preseason projection, but even with Manchester City for most in the league. The draw with Everton likely would’ve dropped their projected total by a point -- they were roughly 50-percent to win and 25-percent to draw -- but their projection now sits at 78 points (while City are still on 85). This isn’t super-precise, but the betting market roughly sees VVD’s injury costing LFC six points over the final 33 games of the year. Extrapolate that out to 38 games, and we’ll say the market sees VVD worth seven points to Klopp’s team.

Despite what the past few seasons have shown, the average Premier League title-winner typically comes in around 85 points. The average relegation team finishes somewhere around 30. Take that difference of 55 points, divide it by 11, and the average championship player is worth five points more than the average relegation player. Assuming that VVD is significantly better than the average championship player, then that seven-point number starts to make sense ... until you remember that Liverpool won’t be replacing their superstar center back with a random dude from West Brom. Some combo of Fabinho, Joe Gomez, and Joel Matip -- all players who played significant roles on these 90-plus-point Liverpool teams over the past two seasons -- will do the deputizing for VVD. Did the Dutchman make these players look better than they are? Is his effect on the game closer to Lionel Messi’s than we might think? Or is the market overreacting?

“On the whole I think that's about right for the market response,” said Omar Chaudhuri, head of intelligence at the consultancy 21st Club. “Personally I think it's too big: Liverpool conceded 7 vs Villa, 3 vs Leeds, 5 vs Man City, 3 vs Watford with VVD at the back, so maybe the system isn't working.”

As a center back, you can play forward passes, you can progress the ball, you can score off set pieces, you can control your defensive space, and you can communicate with your teammates. Your defensive value mostly comes from how well and how much of that defensive space you can control. But as Omar suggests, there’s a limit to just how much of that space any one player can affect. As I wrote about on Friday, the main way opponents have scored against Liverpool is by exploiting the space opposite VVD. Per Stats Perform, these are all the open-play passes that led to goals for Liverpool’s Premier League opponents since the start of 2018-19:

Notice how almost all of them are either passes played to the right side from the center or from the right side. It’s like there’s a force-field around where you’d expect VVD to be positioned, and this speaks to both his excellence when compared to his peers but also the inherent limitations to individual defending. No matter how good of a defender you are, they can always find a way around you.

There’s still so much left to measure and understand about how soccer works, especially with defenders, who aren’t on the ball as much. But Van Dijk does all of the measurable things as well as anyone. Over the past two seasons, he’s in the 95th-percentile or above in all the aerial-duel statistics, and the same goes for how little he fouls and how few attackers dribble by him. He clears the ball at a super-high clip given how much possession Liverpool have. He’s an elite passer for his position, and since 2018-19, no center back in England has started more possessions that led to shots or goals than VVD. The only thing he doesn’t really do is make tackles or interceptions, but it’s not clear that he’d be more effective if he did.

Add it all up, and you have the best central defender in England. Per Sam Goldberg and Michael Imburgio’s DAVIES model that I wrote about a few weeks back, VVD added a league-best 8.13 goals to Liverpool’s performance last season when compared to the average player. But although VVD was the best-performing central defender, those 8.13 goals added were only good enough for 23rd-best in the league. The three players ahead of him were Willian, Tammy Abraham, Richarlison and his current teammate Diogo Jota. No one would say that any of those guys are anywhere near as good at playing their positions as VVD is at playing his. It’s just that the positions they play and the things they get to do in those positions -- mainly, pass the ball into the penalty area, create goals, and score goals -- are more valuable than all the things VVD does over the course of a match. Plus, an error made by a defender is way more impactful than an error made by an attacker, so it’s easier for someone like VVD to lose value, too. As Loran Vrielink -- a tactical coach for VVD’s defensive partner with the Netherlands, Stefan De Vrij -- told me last week: “With a defender, one mistake, and it’s a goal, and you played a bad game. That’s the cruel thing about football. You could not see a winger for a whole game, he’ll score a goal, and people will say he’s the best player on the field.”

It’s similar to the idea of positional value in other sports, too. Baseball was first because baseball is always first: a good center fielder or catcher provides more value than a great first baseman due to what they are asked to do on the field. It’s even easier to understand in the NFL: a pretty solid quarterback is going to affect your team’s ability to win games more than a Hall of Fame lineman because only one of these guys is touching the ball on every snap.

When I spoke to Goldberg, who knows all about the positional spectrum after playing minor league baseball and working for the Chicago Cubs, he made a similar point in a different way. “If you look at elite players in the world, elite forwards are always going to have the highest value,” he said. “The way I explain it to American football fans is like your skill positions are always going to be paid higher than your non-skill positions because they have to be more precise.” Or this way: “You have to be more precise in scoring a goal than you have to do in clearing a ball.”

If a center back can add intangible value, though, then VVD would be the one to do it. The pace he plays at -- just a quarter-step shy of too casual -- certainly makes Liverpool’s defense feel more secure, and perhaps that permeates the rest of the backline. Or, at least it did before this season. There’s also a case to be made that VVD’s unique, near-omnipotent skill set allows Liverpool to play a certain way they otherwise wouldn’t be able to with a more, uh, “normal” player in his spot. Hell, Klopp’s top assistant, Pep Lijnders, has made that case himself: “We can play more aggressive with Virgil because of how he deals with space and longer balls into our back line.” That kind of “value” wouldn’t get directly attributed to Van Dijk himself and would instead show up in the team’s overall performance, which, well, 196 points in two seasons speaks for itself.

At the same time, the parallel stories of VVD and LFC probably are too simple. If soccer really is a complex game, then maybe the story is a little more complex than “buy great defender, have great defense”. Liverpool’s defense had started to improve in the month or two before Van Dijk arrived from Southampton. Plus, they eventually added one of the world’s best keepers in Alisson, they dialed back the high-press a bit, and Klopp tweaked the midfield to focus less on creating and more on locking down the center of the field. It all plays a role.

Perhaps, then, both of these things can be true: Virgil Van Dijk is the best defender in the world, and Liverpool can still win the Premier League without him. If not, then despite a 7-2 loss to Aston Villa and 13 goals conceded in five games, the worst might still be yet to come.