Barcelona attacker Alexis Sanchez will be sidelined for a month after picking up a knee injury during Chile's 3-1 defeat in Serbia on Wednesday.
Sanchez was hurt in a challenge with Serbian midfielder Luka Milivojevic after just 20 minutes of the game, and was replaced by Manchester United's Angelo Henriquez, who went on to score on his full international debut.
Initial reports suggested he had twisted his right knee, but a scan on Thursday revealed ligament damage that will take four weeks to heal.
A Barcelona statement said: "Alexis Sanchez will be out for four weeks. Tests carried out on Thursday confirmed that the player had strained an external lateral ligament in his right leg.
"This means that, if things turn out as expected, the forward will miss seven or eight games for FC Barcelona (Real Zaragoza, Spartak Moscow, Levante, Alaves, Athletic Bilbao, Benfica, Betis and Atletico Madrid)."
If the former Udinese winger, who has a history of coming back injured from international duty, is on track with his rehabilitation, he may be fit to return against Valladolid on December 22.
There is better news for Blaugrana fans, though with club captain Carles Puyol set to return.
Puyol has been training alongside those Barca players not away with their national teams this week and although he has yet to receive a full all-clear from the club's medical staff, the centre-back is expected to be ready to play against Zaragoza this weekend if required.
Alex Song (back) and Adriano Correia (thigh) have also been continuing their recoveries this week. Song is more likely to feature in Saturday's game, for which Sergio Busquets is suspended after picking up his fifth yellow card of the season at Real Mallorca last weekend.