Vorobyov (knee) has recorded four points in seven games with SKA St. Petersburg of the KHL.
Vorobyov suffered an ACL injury while playing for Ufa Salavat (KHL) and is expected to miss significant time, Jordan Hall of NBC Sports Philadelphia reports.
Vorobyov agreed to terms on a three-year deal with KHL club Salavat Yulaev Ufa, per Gorobzor.ru. According to Sam Carchidi of The Philadelphia Inquirer, the club will retain the center's rights by offering him a qualifying offer.
Philadelphia reassigned Vorobyov to AHL Lehigh Valley on Thursday.
Vorobyov has a goal on one shot with an even rating in the last three games.
The Flyers recalled Vorobyov from AHL Lehigh Valley on Wednesday.
The Flyers loaned Vorobyov to AHL Lehigh Valley on Friday.
The Flyers recalled Vorobyov from AHL Lehigh Valley on Wednesday.
Vorobyov was demoted to the minors Thursday.
Vorobyov was promoted from AHL Lehigh Valley on Sunday.