"He is back but he is training with the physio to get more physical condition," Carvalhal told a news conference.
"Next week he can be involved with the team but he has been a lot of weeks away, so the physical condition is very poor. He has been injured for a long time."
Sanches played a key role in Portugal's Euro 2016 triumph but Carvalhal has told the 20-year-old to forget about playing in the World Cup in June.
"I don't think he has any chance of going to the World Cup," the Portuguese manager added.
"I spoke with him because I understand if he is training with adrenaline because he thinks he can go to World Cup, the probability of being injured again is very high."
Carvalhal congratulated newly-crowed Premier League champions Manchester City who his team play on Sunday.
Swansea, 17th in the table, are chasing points to preserve their top-flight status but Carvalhal accepts it will be difficult to get a result at the Etihad Stadium.
"They deserve to be champions, they are the best team in the competition. We are proud to do the guard of honour for them," Carvalhal said.
"It is very tough to play against them because they are a mix of a manager with a very good idea and players who understand football."
(Reporting by Hardik Vyas in Bengaluru, editing by Ed Osmond)
