Barcelona midfielder Sergio Busquets suffered what looked like a serious ankle injury during last night's Copa del Rey semi-final victory over Villarreal.
The Spain international was stretchered off shortly before the interval of Wednesday's 3-1 win at El Madrigal when Tomas Pina landed a late two-footed tackle on his opponent's right foot.
Busquets will now be a major doubt for Barca's Champions League last-16 second leg clash against Manchester City which takes place at Camp Nou in two weeks time, and could also miss El Clasico when Real Madrid arrive in town four days later.
In a statement on the Catalan club's website, officials confirmed that the 26-year-old will undergo tests with medical staff before revealing a prognosis.
"Busquets has a high ankle sprain in his right ankle," read the statement. "He will undergo more tests on Thursday to discover the exact extent of the injury."
Pina was not booked for the challenge on Busquets, but midway through the second half was shown a straight red card for another heavy challenge, this time on two-goal hero Neymar.
It was the Brazilian's brace plus another goal from Luis Suarez that booked Barcelona's place in the final where they'll face Athletic Bilbao on May 30 after recording a resounding 6-2 aggregate victory.
With a 3-1 lead from the first leg, Neymar took just three minutes to put Luis Enrique's side further ahead, before former Barca man Jonathan dos Santos brought the game back level on the night with a well-taken finish.
After the break Suarez restored Barcelona's three-goal lead after rounding Villarreal goalkeeper Sergio Asenjo to slide home soon after Pina's dismissal, and then Neymar notched his second to put the icing on the cake after heading home Xavi's cross.
However, the Blaugrana's delight at progressing to the final of the Spanish cup competition came at a price after losing their star midfielder, potentially for the rest of the season if the ankle injury is as bad as it looked.
"It is the bad news of the night without a shadow of a doubt," Enrique was quoted saying by Sky Sports after the match. "I can't give a diagnosis before the doctors look at him.
"We know he will be out for a while, how long the doctors will decide," - Luis Enrique
The loss of Busquets could prove an expensive price to pay, given the fact he is now regarded as one of Barcelona's most important players at the base of Enrique's three-man midfield alongside Andres Iniesta and Ivan Rakitic.
It remains to be seen whether or not Xavi - at the age of 35 - still has the legs to dominate in the big games, particularly with two season defining encounters coming up in quick concession.
Changing of the guard
There's no doubt that the veteran's eye for a pass is as impressive as ever, but in terms of a tough-tackling physical presence he'll surely struggle to fill the void left by Busquets' absence.
Okay, Barca do go into their second leg against Manchester City with a 2-1 lead from the first encounter, but in Sergio Aguero, Yaya Toure and David Silva, Manuel Pellegrini does have the players to cause their opponents a problem, especially if they are not at their best.
Barcelona fans: How big a miss will Sergio Busquets be if, as expected, he's ruled out for an extended period of time? Share your thoughts below…