Ernesto Valverde has admitted that Barcelona may have to make use of the transfer market in January after Rafinha suffered a serious injury at the weeekend.
The Brazilian midfielder injured the anterior cruciate ligament in his knee during Barcelona's 1-1 draw with Atletico Madrid on Saturday and will undergo surgery next week.
"The injury came as a surprise, because of how it happened. He was able to finish the game against Atletico, then on Sunday [we find out the extent of the problem].
"We will have to look at everything. The January transfer window is close, so we will have to look at the circumstances and see what we do."
Barcelona have been strongly linked with a move for Ajax midfielder Frenkie de Jong, but the Dutch club have made it clear that they will not negotiate mid-season and they strengthened their bargaining position by qualifying for the knockout stages of the Champions League on Tuesday.
Paris Saint-Germain midfielder Adrien Rabiot, who is out of contract at the end of the season, has also been tipped for a move to the Nou Camp. Barcelona would prefer to wait to get him for free next summer but may be tempted to bring the transfer forward by six months.
Barcelona will be boosted by the return of Ivan Rakitic for their Champions League tie against PSV Eindhoven on Wednesday, but Arthur will miss out with an abductor strain.