"He is progressing," Carvalhal told the club's website. "In the beginning they said it could be long-term, but I believe he will come back next month.
"That's my feeling. I think he will be back sooner than we expect."
The Portugal international has failed to impose himself at the Welsh club as multiple injury setbacks have limited him to just 12 league appearances.
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Captain Angel Rangel (groin) and striker Wilfried Bony (knee) are also sidelined for Swansea, who are 16th in the league, while midfielder Leon Britton faces a race to be fit for Saturday's FA Cup tie at Sheffield Wednesday.
(Reporting by Aditi Prakash in Bengaluru)
