The club said he had suffered a ruptured tendon in his right thigh in training last Thursday as the team prepared for the re-start of La Liga next month.
The severity of injury was confirmed after tests on Monday, Villarreal added, but did not say how long they expected him to be sidelined.
The 29-year-old defender joined the Spanish club two years ago from Everton, where he spent three years after a move from River Plate. (Writing by Mark Gleeson in Cape Town; Editing by Pritha Sarkar)
Chris Froome (Stage 2, 2015)
Round 4, Ningbo