There is no weight like the expectation of being the next star of the U.S. women's national team.

Alex Morgan shouldered that as a 20-year-old in 2009, when she joined her first senior training camp with the team. She hadn't yet debuted for the U.S., and already she was drawing comparisons to Mia Hamm, the legend who won a pair of World Cups and Olympics and served as the face of the first generation of American women's soccer players.

On Thursday, 15 years later, Morgan has announced she will retire after one final match on Sunday with the San Diego Wave FC, bringing an abrupt ending to a career that somehow managed to exceed astronomically high expectations on the field, all while redefining the sport off it.

Morgan finishes her career with 123 international goals, which ranks fifth in a decorated pantheon of USWNT goal-scorers. She won a pair of World Cups and played in another final, and her breakout 2012 for the national team was an integral ingredient to U.S. women winning the Olympic gold medal that year.

Her club career includes an NWSL Championship, an NWSL Shield, and a Golden Boot, in addition to another title won in the predecessor league, Women's Professional Soccer.

On the field, Morgan lived up to the hype that preceded her. Her form ebbed and flowed throughout her international career -- she never grabbed hold of the title of world's best player, reaching the shortlist several times. But she largely remained the centerpiece of the USWNT's attack throughout that time and maintained a standard few could match.

Each time her incumbent status was challenged in recent years, she responded with an uptick in form and a reminder of why she was still needed for club and country -- up until recently, at least.

Morgan was left off the USWNT's 2024 Olympic roster, marking the team's first major tournament without the star striker since the 2008 Olympics. It was a bold decision from new USWNT head coach Emma Hayes in her first months on the job, but the Americans went on to win gold at the Olympics in August thanks in part to a new, young forward line.

For all the on-field accolades, Morgan cemented her unique legacy with what she did away from the pitch.

She began her career as a quiet rookie playing in relative anonymity in Rochester, New York. The spotlight often sought out Morgan with the national team, it wasn't something she immediately embraced, like Hamm's designation in decades prior as "the reluctant star." Just as Morgan's game matured beyond a turn-and-run athletic forward into a savvy back-to-goal player, her desire to effectuate progress off the field deepened.

As the face of the sport for almost the entirety of the previous decade, Morgan was a central figure in the USWNT's fight against U.S. Soccer for equal pay, a six-year battle that ended with a settlement and the players declaring victory in 2022. The fight led to equal compensation structures for the U.S. men's and women's teams, as well as revenue sharing and equitable distribution of World Cup prize money between the teams.

USWNT players' long battle with their employer came at a time of increased global advocacy for gender equity in all industries, and it served as a catalyst to further changes throughout women's sports.

When Morgan spoke, people listened. She understood the power of her voice and the prominence of her platform, and that it extended beyond the spotlight of the national team -- including in the National Women's Soccer League.

Morgan was a driving force behind the 2021 revelations that led to the firing of former head coach Paul Riley for alleged sexual coercion of former players. The report also exposed multiple leaders at a league and club level for mishandling accusations that were first made seven years earlier by Morgan's former teammates at the Thorns, Mana Shim and Sinead Farrelly. Morgan used her platform to call out those who ignored the concerns of Shim and Farrelly.

It was the catalyst of a league-wide reckoning with abuse -- "systemic abuse," as an investigation by former U.S. attorney general Sally Yates would later call it. Four coaches, including Riley, were banned for life from the NWSL, while others were suspended, and two team owners were forced out of the league due to their alleged enablement of bad actors.

As a result, the NWSL developed an anti-harassment policy and other safeguards, like a nonfraternization policy and coaches code of conduct. The league and the NWSL Players Association ratified their first collective bargaining agreement in early 2022, raising pay and implementing minimum standards for players.

Although Morgan has mostly deflected credit for her role in sparking change, she was an irrepressible voice for the voiceless in a league where power historically rested almost exclusively with employers. She leveraged her celebrity for allyship rather than purely individual gain. Last month, that dynamic shifted further in the other direction with the ratification of a new CBA that will further raise minimum salaries and provide all players with full free agency upon the completion of their contracts.

Morgan's advocacy for the NWSL -- including serving on the bargaining committee for the latest CBA -- was notable given the historical context that U.S. players' primary source of employment was the national team up until recent years.

"I am so proud of my accomplishments on the pitch," Morgan said in a statement on social media on Thursday. "My dream at a young age was to play professional soccer. I've achieved more than I could ever have imagined through the game, and as proud as I am of my soccer career, I'm equally proud of what I've fought for and helped build off the pitch. Pay equity. Player safety. Visibility and storytelling."

Morgan's career is ending abruptly, even if the writing was on the wall for the 35-year-old. She and her husband, former pro player Servando Carrasco, are expecting their second child, Morgan announced on Thursday.

Morgan is arguably the most defining character of a USWNT generation that continued the program's relentless history of success. Her retirement marks the formal end of an era for the USWNT, which has already begun its next chapter with an Olympic gold medal.

Morgan finds herself in a category with few other peers as a world-class player on the field and a transformational person off it. Just as Hamm came to be known simply as "Mia," Morgan is known to most as "Alex" without any other qualifiers needed.

Athletes often talk about the cruelty of how most do not get to choose how their careers end. Morgan likely would have chosen a different ending on the field than a mid-season exit following a disappointing World Cup and being dropped ahead of the Olympics, but the choices she made throughout her nearly 15 years at the highest level are what define her legacy.

She was hardly reluctant, and in the end, she wasn't "the next" anybody. Morgan was revolutionary.