ARSENAL star Gabriel has been forced off just 16 minutes into his side's Premier League clash with Fulham.
The Brazilian went down in his own box clutching his leg.
He subsequently shook his head as he was replaced by team-mate Jakub Kiwior.
Gabriel's injury comes just seven days before the Gunners' Champions League quarter-final first leg tussle with Real Madrid.
The centre-back has been a near ever-present for Arsenal this season.
He has started 28 of their 30 Premier League matches, missing two in December due to a knee injury.
The commanding defender has also been selected in nine of Arsenal's 10 Champions League games this term, including both legs of their last 16 triumph over PSV Eindhoven.