Barcelona B midfielder Oriol Busquets is set to miss the rest of the season after tearing a knee meniscus in training on Wednesday.
However, Barcelona have not said how long they expect him to be absent for.
Rafinha, who left Barca on loan for Inter Milan in January, suffered a similar injury last April and was initially ruled out for around four months.
However, he suffered a relapse and had to undergo a second operation in October, eventually returning to action last month.
Busquets, 19, had been enjoying a breakthrough season for the B team, making 21 appearances in Spanish football's second tier.
In addition training with the first team occasionally, he made his senior debut in the Copa del Rey.
His absence could provide an opening in the B side for January signing Marcus McGuane, who joined from Arsenal.
England youth international McGuane made his debut from the bench in last weekend's win at Cordoba and could start against Alcorcon at the Mini Estadi on Saturday.