CINCINNATI, Ohio -- In the moments after Atlanta United and United States men's national team defender Miles Robinson went down with a torn Achilles tendon, international teammate Walker Zimmerman got a text from a friend who was inside Mercedes-Benz Stadium telling him that Robinson's injury "looks bad." Zimmerman then found the video on Twitter and saw the responses, and his "stomach just completely sank."

"You start thinking about the timelines, you start thinking about the math, and while it's not impossible to come back, certainly it's going to be an uphill battle," Zimmerman told members of the media on Monday. "I just immediately reached out to [Miles]."

Zimmerman then called up Aaron Long, who almost a year earlier had suffered the same injury as Robinson, and let him know what happened.

"It was a weird feeling I got," the New York Red Bulls defender said upon hearing the news. "It was like heartbreak and instantly, like, 'I need to be the one that that reaches out to him as fast as possible to let him know that I've been through this, and I will help him through this process.'"

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Both players have stayed in steady contact with Robinson since, with Long saying he's called Robinson once a week, the better to answer questions and talk timetables. It helps that Robinson, at age 25, is three years younger than Long was when he was injured, but it's a long process, one that will be filled with ups and downs. Long stressed the best thing Robinson can do right now is be patient.

"There's certain ways you can speed up the rehab process, but you've got to listen to your body," Long said. "I'm just trying to tell him that now's not the time to speed things up. You've got to let it heal for that first month or two."

Every player is different, although for Long, the mental hurdles were the toughest to get over.

"I think more than anything, it's just trying to get your calf and your brain just to be on the same page, and to almost trust yourself in certain moments of like exploding or backpedaling, things like that," he said.

The irony is that Robinson's ascension was aided in part by Long's injury. The Red Bulls defender had been a mainstay under U.S. manager Gregg Berhalter during the first two years of his tenure. With friendly matches against Morocco on Wednesday (7 p.m. ET, stream live on ESPN2) and Uruguay on Sunday, followed by CONCACAF Nations League games against Grenada and El Salvador, the door has been opened for Long to take on a greater responsibility than the substitute role he had in the final qualifying window.

Robinson's injury is the latest to strike a core U.S. player in what has been a year beset by them. Borussia Dortmund midfielder Giovanni Reyna missed most of World Cup qualifying with multiple hamstring injuries. Juventus midfielder Weston McKennie missed the last qualifying fixture window with a broken foot, and has just recently made it back.

But the U.S. team's depth helped carry it to World Cup qualification. When Reyna went out, Timothy Weah and Brenden Aaronson stepped in and produced some dynamic displays on the wing. The same happened when McKennie was injured, with Kellyn Acosta and Luca de la Torre picking up the slack. Now the same will likely have to happen at the World Cup. Long is among those poised to step in, as is Chris Richards, although the latter suffered through ankle and thigh injuries during the latter half of the club season with TSG Hoffenheim.

The center-back position is of critical importance, and this was evident during qualifying. Even on the days when the U.S. didn't play well, the center of defense was usually solid, evidenced by the team's 10 goals conceded in 14 qualifiers. It didn't seem to matter who was on the field either, be it Zimmerman, Robinson or Richards.

Yet chemistry is important, and there will need to be some retooling in this regard during the current camp, as well as in the last international window in September. When asked what traits they would like to see in a center-back partner, both Long and Zimmerman cited good communication as a critical attribute.

"It's more of a mental connection than like anything physical, or like a guy that's fast, or a guy that's strong, or good in the air or anything like that," Long said. "I think it's more just trust in being on the same page in not only like tactical moments, but big defensive moments, like putting out fires. I know where my other center-back is going to be in a moment where we can't talk and we can't discuss things. We know what we're going to do in those moments together."

Zimmerman added, "I love when I have that [communication] on my back shoulder. You know, when I'm getting the instruction, consistently, constantly, that's huge. And when you get games with other center-backs, you kind of develop that almost without them even talking sometimes. You know exactly where they're going to be."

The coming months will reveal the extent to which that familiarity can increase.

Center-back isn't the only area of the field where depth will be tested in the coming months. In fact, while there are plenty of options at the striker position, none have performed with the kind of consistency to make the position their own. That's why Antalyaspor's Haji Wright -- fresh off a 15-goal season in all competitions -- will be the latest to get a look from Berhalter and his staff.

"I think generally being called into camp, it's always an opportunity for you to show yourself and take hold of your position, whatever it may be," Wright said. "I do think it's an opportunity for me and I'm ready to take it."

Left-back has been a position cited by Berhalter as one where there aren't many options behind presumed starter Antonee Robinson. Joe Scally looks to be a candidate given his ability to play outside-back or wing-back on either side -- during the past season with Borussia Monchengladbach he even had a brief spell at center-back -- but so far (and yes, it's early in camp) Scally has lined up on the right side of the U.S. defense. That leaves George Bello as the only alternative to Robinson.

The hope is that the U.S. will enjoy a greater degree of health than it's had in the first five months of 2022.