Euro 2016 starts this Friday. All week, we’ll be highlighting key players in all three phases of the game — defense, midfield, and attack — along with one manager. They’re all among the best at what they do, and the intricacies of their approaches help illuminate how soccer is played today. Check back tomorrow for more.

No one defends anymore. Just ask Paolo Maldini, possibly the greatest defender of all time:

This might seem like the soccer version of the NBA old guard railing against the Golden State Warriors’ destruction of inside-out basketball, but there are plenty of days when Maldini’s statement feels true. I wonder what he thinks about this:

That falling redwood is Jérome Boateng. A month before being chopped down by the world’s smallest lumberjack, Lionel Messi, Boateng’s Bayern Munich manager, Pep Guardiola, called the German defender "one of the three best centre-backs in the world." And Guardiola’s not wrong. In fact, Boateng might be the best center back in the world. But as the game continues to evolve, it’s becoming less clear what that even means.

Traditionally, the center back’s job is to win every ball sent into the box, block every shot he’s near, win every tackle, and never let his striker turn on him. He either lets his man or the ball get by him — but never both. On defensive-minded teams like Leicester City, Atlético Madrid, and whomever José Mourinho is managing, this is still how the center backs play.

But now more than ever, today’s best teams are the ones that keep the most possession. And the defenders on those teams spend the majority of their time doing things other than defending. This started with Rinus Michels and the famous Dutch teams of the 1970s, was caffeinated by Marcelo Bielsa’s frantic approach in Argentina in the ’90s, and popularized (if not perfected) by Guardiola’s Barcelona at the beginning of this decade. Many of the top clubs (Manchester City, Bayern Munich) and national sides (Germany, Chile) tend to involve as many of their players in the attack as possible. That means center backs on the best possession-based soccer teams must be comfortable (if not dangerous) with the ball at their feet, willing to push high up the field, and able to cover all of the space they leave behind.

Possession center backs are a hybrid between an NFL safety and an NHL defenseman — pinning the opposing team in their own half, and chasing back whenever a counterattack breaks through. Boateng, with his combination of range and passing (he completed the most long balls per 90 minutes of any outfield player in the Bundesliga this season), profiles as the ideal center back for an elite, possession-based attacking team.

There are times — like the Messi goal — when he gets isolated against an attacker in too much space, or attempts a heroic interception, and he’ll briefly look like he’s never played soccer before. And that’s the life of a modern center back: No one remembers the 10 times you shut down a counterattack before it could get started; they remember the one time the system broke down and you were sacrificed.

The perceived performance of center backs is system-dependent: It’s easier to look good when two defensive midfielders are in front of you and you never have to stray more than 30 yards from your own goal. (See: Leicester’s Robert Huth and Wes Morgan, two bumbling, 30-something journeymen who turned into a pair of Gandalfs this season under manager Claudio Ranieri, playing behind N’Golo Kanté.) Boateng’s vulnerability makes the Bayern and Germany systems run; his athleticism and ball skills let his teams play much more aggressively and proactively.

At the Euros, there will likely be one or two times when Boateng gets caught on an island and drowned by an attacker, but don’t listen to what Maldini says. Even if Boateng falls on his face again, it won’t mean that he’s not a defender.