
Haghighi featured in all three of Iran's games at the World Cup in Brazil.
Sassuolo goalkeeper Gianluca Pegolo is set to miss a significant chunk of the Serie A season after undergoing surgery on a broken leg.
Sassuolo has also negotiated with AC Milan to sign its goalkeeper Michael Agazzi.
Haghighi joined Russia's Premier League Rubin Kazan on a four-year contract in January 2012 but moved to Portuguese second division team Sporting Covilh on loan last year.
The 26-year-old goalie has already linked with a move to newly-promoted Portuguese football club Penafiel.
By Tasnim News Agency
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