Injured Dutch midfielder Nigel de Jong's World Cup appears to be over, according to a source at the Netherlands Football Federation.
The 29-year-old AC Milan player -- who referee Howard Webb said he would have sent off in the 2010 World Cup final had he seen more clearly his infamous chest high kick on Spain's Xabi Alonso -- suffered a groin injury early on in the Netherlands' last 16 victory over Mexico on Sunday.
"It doesn't look good" a federation spokesman said after de Jong underwent a medical examination on Monday.
Further tests will be conducted in a few days ahead of the Netherlands quarter-final date with Costa Rica on Saturday.
De Jong came off the field against Mexico in Fortaleza after just nine minutes, with Dutch coach Louis van Gaal declaring the injury was a "big setback" as he plans for the Salvador clash.