Transfer expert Fabrizio Romano confirmed the agreement this week, with the move expected to be formalised next month. Barco had pre-empted the announcement by posting an emotional farewell to Strasbourg on social media.
"Today I say goodbye to this club," Barco wrote. "I always gave everything on the pitch in every game for this shirt.
"I want to thank my team-mates, who made everything easier for me; Liam Rosenior and his staff for the confidence they showed in me and for helping shape me as a player; Gary O'Neil and his staff for understanding me and helping me improve."
Barco joined Brighton & Hove Albion from Boca Juniors in January 2024 for £7.9 million, but struggled to establish himself at the Amex Stadium, making just seven appearances. A loan move to Strasbourg in January 2025 changed the trajectory of his career. He impressed sufficiently to earn a permanent transfer to the French club for £10 million last summer.
At Strasbourg, the Argentine was converted from a left wing-back into a midfielder by then-manager Rosenior, a shift that unlocked his best football. He made 43 appearances this season, contributing three goals and nine assists. Former Chelsea manager Rosenior had reportedly tried to take Barco to Stamford Bridge before his own dismissal in April.
The transfer is the latest in a series of moves between the two BlueCo clubs. Reports suggest it will be the 13th deal between Chelsea and Strasbourg since the start of last season. Goalkeeper Mike Penders is also under consideration for a return to the Bridge following a successful loan spell.
Barco could become the first-choice left wing-back under incoming Chelsea manager Xabi Alonso, who officially takes charge on 1 July, if Marc Cucurella departs.
New manager, familiar business model. Strasbourg will make a substantial profit on a player they paid £10 million for.