Jonathan Wilson, author of Inverting the Pyramid, wrote in 2009 that fullback is the most important position in soccer. This importance is the result of a couple trends in tactics. He writes: “as the gradual move to a single striker has led to a return to a back four, the full-back has again taken on attacking importance.” Furthermore, with true wingers becoming rare, “the full-backs are the only players on the field who regularly have space in front of them.” Michael Cox included the rise of attacking fullbacks as one of the 10 biggest tactical shifts of the 2000s. The tiki-taka tyranny of Barcelona and Spain highlighted the significance of central midfielders, but even that system relied on fullbacks like Jordi Alba providing width.

DeAndre Yedlin reflects the recent ambiguity of the fullback role. He starts at right back for the Seattle Sounders, but there are few who would describe defending as the best aspect of his game. A few months ago, he made a name for himself at the World Cup appearing largely as a midfielder, not a fullback. In that midfield role, he was a key part of the build up in the USMNT’s second goal against Portugal. In the aftermath of Brazil, he was the subject of speculation and bidding from several European clubs, and eventually a deal was agreed to sell him to Tottenham Hotspur. But at the moment he is still in Seattle, still playing right back, and it’s worth taking a look at how he fills that role.

On television, the modern fullback is a surprise artist. With the ball in the center of midfield, he starts off-screen. And then there’s a streak of green (or white or blue) racing across the top or bottom and OH MY GOD WHY DOES HE HAVE SO MUCH SPACE? Those are the sort of runs that DeAndre Yedlin loves to make. With his pace, an empty patch of the field serves as an invitation that he almost never turns down. If the Sounders had his way, this would end with a cross into the box every time.

Per Ted Knutson and StatsBomb, Yedlin attempts a bit more than four crosses per game and completes one. For comparison, Spurs as a team completed just three crosses in their opening two Premier League games this year, with two resulting in goals. Now, Yedlin is not the type to run at and beat a defender with the ball, so the question becomes how to create the space for him. Above, you see Brad Evans drifting inside to open up the wing for Yedlin to sprint into.

Here, the Sounders simply play a numbers game and overload the right side. Marc Burch cannot defend both Evans and Yedlin.

Yedlin and Evans have symbiotic relationship on the Sounders’ right wing. Yedlin is a fullback who likes to get forward; Evans is a midfielder who Jurgen Klinsmann often used as a fullback in last year’s World Cup qualifiers. That affords the Sounders a bit of fluidity, with Yedlin and Evans trading places in the hopes of dragging the defense out of position.

Spurs fans might recognize the above gif as a mirror of Tottenham’s fourth goal against QPR. But as with any bit of attacking movement, it doesn’t always work out so prettily. Yedlin will make runs that, for one reason or another go unrewarded.

If the Sounders maintain possession, this isn’t necessarily a bad thing. Possession is the security blanket of attacking fullbacks: if your team has the ball, you can make attacking runs without too much worry. In this respect, Yedlin is a better fit for Spurs, who like to control the ball, than, say, Burnley.

When the Sounders lose the ball, things become complicated. Evans’ versatility helps the Sounders in this regard, but not every team has that luxury. “Andros Townsend playing right back” sounds like a bad idea. It’s here, on defense, that Yedlin becomes harder to measure. He commits about 1.6 fouls per game, but how do you quantify the fouls that his teammates are forced to commit because Yedlin is out of position?

This is really the root of Yedlin’s defensive worries. He doesn’t give the ball away stupidly in his own half, nor does he make particularly bad challenges; he’s picked up just 6 yellow cards in his 2-year MLS career. Taylor Twellman recently praised Yedlin’s maturity and composure when forced to defend one on one. Here he shuts down Darlington Nagbe.

But as long as Yedlin is bombing forward, he will be leaving space in behind him. In some ways, his flaws are philosophical, not personal: how much do you want your fullbacks joining the attack? If you say “a lot,” then you have to accept that things like this can happen:

The space that Yedlin abandons needs to be covered, be it by a center back or a midfielder. But Yedlin’s forays forward aren’t necessarily a zero-sum game. His pace, at least at the MLS level, is often enough to erase the mistakes he makes in positioning:

There is a lot that remains unanswered about DeAndre Yedlin’s future. Will he be able to get a work permit? Will he go on loan? Can he find playing time in a Tottenham squad that currently includes Kyle Walker and Eric Dier? Would he be better off as a midfielder? But he’s 21, and he turned that age more recently than I did. Yedlin has the physical gifts needed to compete on a high level. And England has a soft spot for players whose physical talents outshine their technical abilities.

More presently, he is a solid right back in MLS and part of the reason why Seattle has the best record in the league.