Angel City FC forward Alyssa Thompson boarded a London-bound plane from Los Angeles on Wednesday as six-time reigning English champions Chelsea attempt to finalize a deal for the American, multiple sources confirmed to ESPN.

England’s transfer deadline closes at 11 p.m. local time Thursday. Multiple sources confirmed that Angel City and Chelsea have not yet agreed to a deal, but Thompson’s departure for London signals that a transfer agreement would be reached.

Thompson, 20, sat out Angel City’s NWSL match Monday and was listed as an excused absence. Coach Alexander Straus, who took the job in June, said after Monday’s 2-1 victory over Bay FC that the previous days had been “difficult.”

Angel City has not commented on the transfer saga as it has played out over the past week.

Thompson has scored six goals and added two assists for Angel City this season in the NWSL. In January, Thompson signed a three-year extension with Angel City that runs through the 2028 season.

Her 19-year-old sister, Gisele, also signed an extension through 2028 at the same time. Thompson is a Los Angeles native who skipped college — after committing to Stanford — to turn professional. Angel City selected her No. 1 in the 2023 NWSL draft.

Thompson became the first player to be drafted straight out of high school. She was the youngest player on the United States’ 2023 World Cup team later that year at 18. Thompson debuted for the senior USWNT against England on Oct. 7, 2022, in front of 90,000 fans at Wembley Stadium in London.

Chelsea is already home to United States international forward Catarina Macario and USWNT vice-captain and defender Naomi Girma. The club paid a then record $1.1 million transfer fee to San Diego Wave FC for Girma in January.

Chelsea have made a point to go after more USWNT talent in recent scouting efforts. A fee for Thompson, one of the NWSL’s emerging stars, is expected clear the $1 million threshold at minimum. The Orlando Pride set a record in August when the NWSL team paid $1.5 million to Tigres for Mexico forward Lizbeth Ovalle.

ESPN’s Emily Keogh and Charlotte Gibson contributed to this report.