Lukas Engel has left Middlesbrough to join FC Cincinnati on loan until the end of the year.
The Danish defender will be with the US side for the whole of the 2025 MLS season.
Engel, 26, moved to the Riverside in August 2023 and played 41 games last season, scoring twice.
But he has been limited to 12 appearances this term, with his only league start since August coming on New Year's Day.