The striker was taken off in the 16th minute of the game at Celta's Balaidos home, which the Galicians won 4-1, after winning a penalty from a foul by Federico Fazio.
Coach Juan Carlos Unzue told a news conference that the former Manchester City and Celtic striker, who joined Celta in 2015, could be out for up to six weeks.
Guidetti scored nine goals in all competitions last season as Celta reached the semi-finals of the King's Cup and the Europa League.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
Celta open their league season at home to Real Sociedad on Saturday.
(Reporting by Richard Martin; Editing by Clare Fallon)
Share
