Graham Zusi's transition from midfield to right-back a boon for the U.S.

Did he anticipate too much grunt work on defense? Not as much chance to get into the attack?

"Maybe. I didn't really know what to expect," he said. "I know that I had had success the one or two times I had done it, but those were both home games in Kansas City where we have 80 percent of the ball and the outside backs are allowed to get forward a ton. I wasn't sure it was going to be all that. But it's been a challenge, and something I've enjoyed learning. It's just a different look and a new feel and sometimes that can be exciting. I've enjoyed the challenge of learning that new position."

As Zusi describes the transition further, he quipped that "it's a way to follow in the footsteps of DaMarcus Beasley", another U.S. midfielder who moved to a spot in the back. But more than once he says the switch has been a way to "further my depth."

Initially, it seemed like an awkward choice of words, but it actually fits. The change has seen him improve on his already impressive versatility, expand his defensive skill set, and will likely see him increase his longevity in the game.

"I think he's done well," said Arena about Zusi. "Those aren't easy transitions, and it's taken him some time to get comfortable there. But I thought as we got in towards the end of the Gold Cup, you could see he's really grown into the position. He's comfortable in terms of his defensive responsibilities, and he's always going to be comfortable going forward, which is a real plus for a player in that position."

Arena's confidence in Zusi seems set to extend into Friday's critical World Cup qualifier against Costa Rica, one where the U.S. heads into the match clinging to the third and final automatic qualifying spot by just a point over Panama. Usual starter DeAndre Yedlin is out with a hamstring injury, yet Arena chose not to call up Eintracht Frankfurt defender/midfielder Timmy Chandler. Another candidate, Fabian Johnson, indicated that he expects to log minutes on the left side of midfield on Friday. That leaves Zusi and Eric Lichaj as the remaining candidates, and given Arena's preference for Zusi at the Gold Cup, he seems likely to get the nod against the Ticos.

Zusi has certainly undergone something of a crash course in learning the position. He has long been an effective, no-frills kind of player, whose most famous goal remains the equalizer in a World Cup qualifier against Panama in 2013, one that had the unintended consequence of keeping Mexico's qualification hopes alive. But he admitted that the last two seasons his impact has been limited due to a series of injuries, and that he "never really got into the flow of the season."

The switch of positions then has been a "refresher" for him, and in the process allowed him to be a more consistent contributor in 2017.

"That's all I care about," he said. "I don't really care where I am on the field. I'm not a huge stats guy. But just helping my team in the best way possible, that's when I'm going to enjoy myself the most."

The switch has posed challenges on a number of fronts. You don't crack Vermes' lineup without a willingness to put in the defensive work, so Zusi already had a solid base from which to work. But being the last line of defense requires a more measured approach. Not only must he concern himself with the spaces in front, but behind as well, which means channeling his aggression in the right moments. He's learned that against quick opponents, it's oftentimes better to delay and wait for help.

Deciding when to go forward and when to stay has a bit more risk attached to it now as well, though he's been encouraged by his coaches at both the club and international levels to go with his instincts.

"I've found that if I'm thinking too much about, 'Should I go this time or should I stay?' sometimes you can be off just a little bit," he said. "As the play develops I can still use my attacking mindset to maybe recognize what's developing coming to my side and able to get forward. The good thing with both Kansas City and the national team, they expect me to get forward. It's not something where they're holding me back if I'm doing what I naturally what I want to do. It's not free rein, that's not the right term, but I think that's why I'm in that position, to provide a bit into the attack as well."

The biggest challenge for Zusi has been staying focused and in sync on defense with his teammates for 90 minutes. In the world of defenders, only the paranoid survive.

"I'm not saying that players ahead of you or forwards or midfielders check out, but if you're a forward and the ball has gone past you or switched, you kind of just make your way back into your space," he said. "As a defender, you literally are constantly connected with your back line, constantly moving up and back. It's a position where I've found that physically it may not be as demanding as a midfield position, but mentally it is draining. After games you feel mentally drained because you have to be locked in the entire time, or you can be punished."

Costa Rica will certainly challenge Zusi and the rest of his teammates. Ticos midfielder Bryan Ruiz remains the linchpin of the team's attack and is capable of popping up anywhere on the field to deliver incisive passes. Christian Bolanos is another attacker who will venture inside to find the game. Left wing-back Bryan Oviedo can certainly be expected to venture into Zusi's zone as well.

"They're kind of a free-flowing team, they go in and out," said Zusi about Costa Rica. "They don't really have a very set, locked down approach, their spatial patterns aren't set. Communication is going to be huge for us; the switches, knowing what's in front of us. The right center-back, the right-back, the right interior midfielder, the right outside mid, the communication has to be constant. Whatever they bring I think we'll be ready for."

Given the stakes, Zusi and his cohorts will need to be.