Barcelona have revealed that Joao Cancelo suffered "a left MCL strain" during Thursday's La Liga contest with Las Palmas, with the defender forced off in the early stages of the match.
Cancelo was withdrawn in the 11th minute of what proved to be a 2-1 win for Barcelona, with Ilkay Gundogan netting a 93rd-minute penalty to secure a vital three points for the reigning champions.
The success came at a cost, though, with Cancelo picking up a knee problem which has been confirmed by the club as an "MCL strain".
"Tests carried out this morning have revealed that first team player Joao Cancelo has a left MCL strain. He is out and his recovery will determine his availability," read a statement from the Catalan side.
There was initially fears that it could be a long-term problem, but Barcelona boss Xavi said during his post-match press conference on Thursday that the issue "doesn't seem serious".
Cancelo will be absent for Barcelona's Copa del Rey contest with Barbastro on Sunday, in addition to the semi-final of the Spanish Super Cup against Osasuna.
The Portuguese will also be missing for a potential final against either Real Madrid or Atletico Madrid, and the nature of the issue could also keep the 29-year-old out of the league games with Real Betis, Villarreal and Osasuna towards the end of the month.
Cancelo is one of six Barcelona players currently on the sidelines through injury, with Gavi, Marc-Andre ter Stegen, Pedri, Inigo Martinez and Marcos Alonso also absent.
The reigning champions trailed 1-0 to Las Palmas on Thursday before recovering, and Xavi said after the clash that he was always confident that a comeback would occur.
"In the second half we did well. In the first half, we saw easy spaces in behind the defence but we rushed passes. In the second half we were more calm," the head coach told reporters.
"We came back against a team that no team had come back against this season. I had a lot of faith. At half-time, I told the players that we would win 3-1.
"The key of the match was to attack the space in behind their defence. We trained for that the whole week, but we didn't do well. A lot of offsides, horizontal passes, and low precision. We had to be diagonal.
"The goal that we conceded was our mistake. There is always tension. There are many things when playing a football match – nerves, pressure – but if you talk to me about the penalty, for me it is a clear penalty."
Barcelona are currently third in the La Liga table, boasting 41 points from 19 matches, which has left them seven points behind second-placed Girona and leaders Real Madrid.
