Manchester City striker Sergio Aguero is recovering from an arthroscopy on his knee.
Aguero missed Saturday night's win at Tottenham after suffering an injury setback, but manager Pep Guardiola said last week he remained hopeful the 29-year-old would be available for the "last games" of the season.
No timescale for his recovery has been given but, with City already crowned Premier League champions, the World Cup will be his main target.
Aguero has not started a game since City's victory over Chelsea on March 4, although he was an unused substitute against Basel on March 7.
Following his lay-off he returned to action as a late substitute in the derby defeat to Manchester United on April 7, when he was hurt in a controversial challenge from Ashley Young that went unpunished.
After that he was unable to train fully in the build-up to the second leg of City's Champions League quarter-final against Liverpool on April 10. Again, he was only able to appear as a second-half substitute.
Guardiola said: "I don't know (when he will be fit). We cannot forget he was two months injured.
"He made a huge effort, because after the action from Ashley Young against United, with problems in the knee, he could not train. Afterwards he could not run.
"I don't know if he will be ready for Swansea (on April 22). Hopefully (he will be back) for the last games, if we need him, and especially for the World Cup."