The Miami Marlins wanted to hire a president of baseball operations over general manager Kim Ng despite her constructing a playoff team this year, leading to her departure from the organization Monday, sources told ESPN.

Ng, 54, was the highest-ranking woman in a major men's North American professional sports front office. The Marlins hired her in November 2020 as general manager -- the first female GM in MLB, the NFL, NBA or NHL -- and her contract included a mutual option for 2024. In a statement, Marlins owner Bruce Sherman said the team exercised its end of the option but Ng declined hers.

Ng was offered a contract extension, sources told ESPN's Buster Olney, but she turned it down.

The team's desire to hire someone over Ng to run baseball operations surprised fellow executives around baseball, who lauded her work with the 2023 Marlins. Her deals for third baseman Jake Burger and first baseman Josh Bell at the trade deadline fortified a weak offense and helped push the Marlins to an 84-78 record and the final wild card slot in the National League.

Despire a -57 run differential, the largest ever for a playoff team, he Marlins improved by 15 games from the previous season following Ng's hiring of manager Skip Schumaker, who is under contract for 2024 with a team option for 2025. The playoff appearance, in which the Marlins were swept by the Philadelphia Phillies in the wild card round, was the first for the team in a full season since 2003.

Ng, who declined comment when reached by ESPN, had weathered significant tumult in the organization during her three years there. In February 2022, Hall of Famer Derek Jeter stepped down as CEO of the Marlins after disagreements with Sherman on the direction of the franchise. Four months later, the Marlins fired vice president of player development and scouting Gary Denbo, who had clashed with people inside the organization.

With Ng in charge, the Marlins took steps forward. Left-hander Jesus Luzardo, acquired at the deadline in 2021, grew into a reliable starter in his first full season in Miami's rotation. Rookie Eury Perez, who debuted this year just 27 days after his 20th birthday, was a revelation. Despite the struggles of reigning NL Cy Young Award winner Sandy Alcantara, who recently underwent Tommy John surgery, the Marlins' starting pitching was a strength.

The offense still struggled but received a jolt from second baseman Luis Arraez, who won the NL batting title with a .354 average after Miami acquired him for right-hander Pablo Lopez over the winter.

While Miami's free agent signings of third baseman Jean Segura and first baseman Yuli Gurriel flopped, their replacements, Burger and Bell, helped them navigate a tight NL wild card race to lock down the final spot.

In 53 games, Burger hit .303/.355/.505 with nine home runs while Bell hit .270/.338/.480 with 11 home runs. Burger is under team control for five more season and Bell for another year, though he does have an opt-out this winter.

"We thank Kim for her contribution during her time with our organization and wish her and her family well," Sherman said in the statement. "We will immediately begin a thorough and extensive search for new leadership as we plan to continue to invest in the Marlins organization both on and off the field."

The only other current job opening for a head of baseball operations is with the Boston Red Sox, who fired chief baseball office Chaim Bloom in September.