Carles Puyol is facing an extended period on the sidelines after undergoing knee surgery on Thursday, but is likely to return to action before the end of the season.
Puyol, 34, was omitted from Vicente Del Bosque's Spain squad after complaining of soreness following Barcelona's 4-0 win over AC Milan on Tuesday.
Barcelona confirmed on their official website that Puyol "underwent an arthroscopy on Thursday evening in order to clean up his right knee".
Puyol will miss both legs of the Champions League quarter-final tie with Paris Saint-Germain next month and will need to recover quickly to make a possible semi-final. With the final scheduled for May 25 at Wembley, he could be back in time if Barca get that far.
Surgeon Ramon Cugat told the Barca website: "He [Puyol] will decide the timing of his return. It could be a month and a half, two or three months. With a normal person you would say leave it a few months until it is better; with Puyol it could be four, six or eight weeks."
Fellow surgeon Ricard Pruna added: "He has been carrying this problem since October, and the game at Getafe. It hasn't gone away. He said he couldn't stand it anymore, and he wanted to use the break for internationals to try and be in top shape for the end of the season. If he didn't do it now there was a risk it could get worse.
"There is a chance he could be back in time for the [Champions League] final. We would all be pleased if that were the case because it would mean we had reached the final."
Puyol underwent similar surgery last summer and missed Spain's successful Euro 2012 campaign, but Cugat revealed the latest operation was not as complicated. He said he was "optimistic'' Puyol would be able to continue with his career after recovering.