There are captains, and then there is Becky Sauerbrunn.

The U.S. women's national team defender is, as several teammates have described her over the past couple of years, the team's "moral compass." She is the liaison between head coach Vlatko Andonovski and a team of young players who mostly were not around for the past two World Cup triumphs, each of which featured Sauerbrunn anchoring the back line.

Becky Sauerbrunn is irreplaceable for the USWNT as a leader on and off the field. And yet, Sauerbrunn will not be at the 2023 World Cup, confirming Friday that she will miss out on a fourth World Cup and a shot at a third title due to injury.

It's worth noting this wasn't a new injury. Sauerbrunn missed all of May with a foot injury, returning to action for her club, Portland Thorns FC, for 24 minutes off the bench on June 3 in a victory over rival OL Reign. That brief appearance caused a significant setback, sources tell ESPN -- significant enough that even the month remaining before the U.S. opens its campaign, it was deemed insufficient for her to heal.

"Heartbroken isn't even the half of it," Sauerbrunn said in a statement posted to her social media accounts late Friday.

On the field, Sauerbrunn leaves a void in a position lacking both depth and experience.

For the past year, Andonovski had settled on a rotation of three primary center backs: Sauerbrunn, Alana Cook and Naomi Girma. Cook and Girma are promising young talents, but between them they have just 39 international caps. Sauerbrunn has 216 caps. She was the only carryover on the back line from the USWNT's 2015 World Cup win to the 2019 repeat win. Her performance in 2015, when the U.S. tied a World Cup record for consecutive shutout minutes, cemented her as one of the world's best defenders.

Despite that abundant talent, the bigger loss for the U.S. at the World Cup will be Sauerbrunn's leadership. She is the constant veteran presence on a team that is more inexperienced than it has been in decades as it works through a generational transition. Sauerbrunn's analytical mind is an asset on and off the field, both to teammates and technical staff.

"Becky is someone that I bounce lots of ideas off, lots of things," Andonovski told ESPN earlier this month, just before Sauerbrunn's injury setback. "If I have a question or if I'm not sure about something, I bounce it off of Becky. Even simple questions.

"Literally, right now, I called her yesterday afternoon and I said, 'Hey Becky, tell me what you hear when I say this.' It's a great understanding of -- she feels safe telling me what she feels knowing that there won't be any repercussion no matter what. She's not afraid of telling me things that I sometimes don't want to hear."

Andonovski and Sauerbrunn go back a decade, to a time before either of them had really grown to fame. The arcs of their careers are inherently intertwined, with Sauerbrunn rising from a U.S. reserve player to irreplaceable starter, and Andonovski going from being a self-proclaimed "nobody" to having one of the biggest coaching jobs in the sport.

The coach and player crossed paths somewhat by chance in 2013 at the start of the National Women's Soccer League. Sauerbrunn was allocated to FC Kansas City, a team that had little information around it and whose ownership lacked any background in the women's game. Andonovski had played for the indoor soccer team of shared ownership while taking up coaching. He marched into his FC Kansas City interview over-prepared, with binders of research he had poured over, and got the job.

Six years later, he did the same thing with U.S. Soccer, this time as a coach with two NWSL championships under his belt -- with Sauerbrunn as his captain for each -- and as a coach now known to have an eye for development. He had prominently called his shots, too, like when he said Sauerbrunn would become one of the best defenders in the world.

Andonovski initially waited to name a captain when he took the USWNT coaching job in late 2019 after coach Jill Ellis stepped down. He wanted to observe the team in its element first and then decide, putting aside any biases since he'd coached so many players in the NWSL. Still, he arrived in a familiar place: with Sauerbrunn as captain.

"Vlatko knows what I'm about, I know what he's all about, so I think it does afford us a bit more open communication," Sauerbrunn told ESPN in an interview earlier this year. "When one of us is -- not stepping out of bounds, but if I feel like he could be doing this and it would be perceived in a way that he doesn't see it being perceived as, I can say that to him and I think he will trust me. Even though he doesn't initially see it, I think he'll trust that I'm hearing it this way so a lot of other people would be hearing it that way.

"I think that has helped us troubleshoot some issues through the years. And he's done that for me as well. I think he can look at me and be like, 'What's wrong?' And I'm like, 'OK, I can tell you what's wrong.'"

Bridging the USWNT's generations

Humility is Sauerbrunn's defining characteristic, and part of why she is so universally admired. Sauerbrunn was not pegged for greatness at an early age. She has said through the years that she wasn't sure if she was good enough for the international stage. When she made the 2011 Women's World Cup roster, her surge through the USWNT ranks had seemingly come out of nowhere. Fifteen years after her debut, however, Sauerbrunn's name is now among the best.

"Not at all something I would have envisioned," Sauerbrunn told ESPN earlier this year. "I feel like I barely scraped by making that 2011 roster. Then to make it three more after that, and to have won two of them -- hopefully a third -- I never expected one cap with the national team, let alone potentially going to a fourth World Cup. So, this has all been a very pleasant surprise."

One of the recent goals of Sauerbrunn, who was previously a U.S. co-captain in 2016 and 2017 under Ellis, has been to create a more welcoming atmosphere for young players. Many joined the team for the first time over the past two years. After the 2021 Olympics, where the U.S. scraped by to salvage a bronze medal, Andonovski implemented mass changes with an eye toward the 2023 World Cup. A generational transition was afoot, and an influx of young, hopeful talent was about to get an extended tryout.

The constant among the veterans was Sauerbrunn. Other younger regulars with World Cup experience, like Lindsey Horan and Rose Lavelle, stayed with the team, but Sauerbrunn was initially the last standing of the old guard. Forwards Alex Morgan and Megan Rapinoe spent time away and eventually earned their recalls in 2022, but Sauerbrunn held the task of introducing an entire new group of players to the team's culture.

USWNT training camp is a notoriously difficult place, one where the 1% of 1% constantly fight to earn or keep a place. Distinguishing the difference between a starter and someone dropped from a roster can be difficult for the untrained eye. In the past, when U.S. Soccer contracts were the primary forms of income for players, there were major financial implications, raising the stakes.

"When I first got onto the team, I would say that it could be really lonely," Sauerbrunn said, noting that she heard the same from other newcomers in recent years. Things have changed lately -- she hopes, at least.

"This environment, through the years, has gotten progressively more difficult just for the team that we're on and the stage that we're on and the eyes that are on this team, the competition that is in play," Sauerbrunn said. "So, it's already extremely stressful, so what we tried to do was make a conscious effort to not add stress by making it, you come in and no one's really greeting you or no one's explaining things or giving you pointers. So, we've made a really conscious effort to be more welcoming. You're either going to make it or you're not, and a lot of it has to do with that stress and how you deal with it."

There have been major setbacks along the way to this World Cup.

Most obvious is the long list of injuries that now includes Sauerbrunn. Catarina Macario, the team's generational attacking player capable of dominating in the No. 9 or No. 10 role, tore her ACL last spring and won't play at the World Cup. Mallory Swanson, the dynamic, goal-scoring winger, tore her patella tendon in April. Midfielder Sam Mewis had a lingering knee problem that turned into a long-term injury.

Then there were the red flags from matches late in 2022. Consecutive defeats to England, Spain and Germany brought the first three-game skid for the USWNT in 20 years. The midfield, an area of dominance for the team at the 2019 World Cup, struggled throughout the past year.

Now comes the World Cup spotlight, a more intense one than many players have ever witnessed. Although Sauerbrunn won't be with the players, she has laid the groundwork for the culture that could make the USWNT's World Cup.

"It is still ongoing," Sauerbrunn says about young players adapting to the national team. "Vlatko has a very different style that is probably different from how they've been coached, whether [in college], high school. In some ways, Vlatko can be very blunt, and for some players, that's just not a coaching style that they've had before. I think getting over that initial 'woah,' where your head goes back a little bit and just knowing that he's only telling you things because he wants to make you better -- the more he talks to you, the better it is -- I think that's kind of a mindset shift that some players needed to realize."

Andonovski said Sauerbrunn does not just talk the talk, but she walks the walk. This is true away from the pitch, too.

In 2020, Sauerbrunn became the first president of the USWNT Players Association. She was one of five high-profile players to file a formal equal-pay complaint with the Equal Employment Opportunity Commission in 2016, a motion that formally began a six-year legal battle with the federation that ultimately led to a new collective bargaining agreement with improved conditions for the women and shared World Cup prize money with the men.

Earlier this year, she wrote an opinion piece defending transgender youth in sports and pushing back against proposed legislature in her home state. In addition to solidarity with Canadian players ahead of that Feb. 16 match in Orlando as Canadian players fought with their federation over pay, U.S. women's players wore tape around their wrists with the saying, "Defend Trans Joy," a show of support for transgender people in a state where their rights have been challenged.

Sauerbrunn's growth into a leader could be seen as a natural maturation. Andonovski says it is more noticeable now, but it was always there. Look back to the 2015 World Cup semifinal, when a young Julie Johnston (now Ertz) broke down in tears on the field thinking she was going to be sent off for a challenge as the last defender. She was spared with just a yellow card. Stepping up to calm her in the moment was Sauerbrunn, who Ertz later that day called "her backbone."

When Sauerbrunn was named captain in 2021, Mewis said: "Sometimes I look to Becky like my moral compass. Like whatever she is doing is what I know is right, so I should probably do the same thing."

This underscores why not having Sauerbrunn in Australia and New Zealand for the World Cup starting in July is such a loss for the USWNT -- and also why Sauerbrunn's impact on the team won't disappear without her physical presence there either.

In the statement she posted Friday, Sauerbrunn said the team has her "unwavering support" and "unyielding belief." She also shifted attention back to the roster of set to be announced on Wednesday -- those 23 players are tasked with winning the World Cup without her.

Sauerbrunn has been keenly aware that despite her influence as a veteran who has anchored the team, it's the newer, younger players who must ultimately lead the way for the USWNT in this World Cup. Now, they embark on a journey to New Zealand without her, their captain, their leader. They will carry with them Sauerbrunn's lessons.

"It's an interesting dichotomy," Sauerbrunn told ESPN earlier this year, "because I am part of these two [World Cup titles] but not a lot of my teammates were part of that, too, so this is a completely new thing for them. For them, they are not defending anything. I don't want to feel like that, either. To win a third would be amazing. That's what this team wants to be about. We want to be a team that does something like that. It's trying to keep everything into perspective and not putting too much into one thing."