Barcelona lost defender Sergino Dest to injury during the team’s 2-1 Europa League win over Galatasaray on Thursday night in Istanbul.
The USMNT star started the game but was forced off on 56 minutes and replaced by Ronald Araujo with what appeared to be a hamstring problem.
It’s a tough blow for Dest who had been enjoying a strong game against Galatasaray and has looked much-improved in recent weeks.
Dest now looks to be a real doubt for Sunday’s Clasico against Real Madrid, although Xavi may have been planning to start Dani Alves at right-back in any case at the Bernabeu.
La Liga then pauses after Sunday’s big match for an international break with Barca’s next fixture not until April 3 when the Catalans take on Sevilla at the Camp Nou.
Dest’s USMNT side are obviously in action in the meantime and are scheduled to take on Mexico, Panama and Costa Rica in their final three World Cup qualifiers.
Coach Gregg Berhalter is due to name his squad later on Thursday but it remains to be seen if Dest will be fit enough to link up with his international team-mates.