Portland announced they had agreed to terms with Carpenter, pending receipt of her P-1 Visa and International Transfer Certificate (ITC). 

Thorns FC head coach Mark Parsons said it is an exciting move for the club and Carpenter. 

“We are signing a powerful, attacking fullback that can help us now and also has huge upside in the long term," he said.

"Ellie has strong technical ability with an attacking attitude that will add to our play out of the back.

"Her winning mentality to improve and compete makes her a great addition to our group,” Parsons said.

Carpenter will be the first NWSL player to be born in the 2000s.

She has scored one goal in 13 caps since making her international debut and was also the youngest member of Australia's 2016 Olympic squad. 

Carpenter spent the W-League season with Canberra United where she was named both the 2017-18 Player of the Year and Supporters’ Player of the Year at their awards night.

“Ellie is regarded as one of the top young players in the world and we are delighted by the opportunity to further her development,” said Gavin Wilkinson, general manager and president of soccer for Thorns FC.

“She fits a positional need and we look forward to her joining the club after she turns 18.”

Carpenter will join the club after the conclusion of Asian Cup on April 28.