Rangers’ five Dutch stars fear they been unwittingly doped by their own national team medics.
The Dutch Football Association, KNVB, have launched at investigation after Frank de Boer, the twin brother of Rangers midfielder Ronald, tested positive for nandrolone.
He became the second Dutch international to have failed a post-match drugs test, with Edgar Davids of Juventus the other.
Both failed tests after international duty with Louis van Gaal’s team and that link could prompt tests for every player to have worn the orange shirt in the past year.
KNVB confirmed that the investigation will look into food supplements given to the entire squad at international gatherings.
As well as de Boer, Rangers have seen Arthur Numan, Giovanni van Bronckhorst, Bert Konterman and Fernando Ricksen spend time this season on international duty.
A KNVB spokesman said: ‘‘Although KNVB have no doubts about the integrity of their medical staff it was still decided to start an independent investigation into the food supplements that were given to the players during recent gatherings of the Dutch national team.
‘‘KNVB have asked the Dutch Olympic Committee, being the governing sports body in the country, to advise KNVB how this investigation should be set up and who should make this analysis. KNVB also informed the Ministry of Sports about this procedure.’’
Davids and Frank de Boer are both currently awaiting the results of a second set of tests.
Both players insisted they had not knowingly taken any banned substance.
Dutch medical chief Fritz Kessel admitted: ‘‘Supplements are involved but they do not concern food and the players have been taking these when with the international squad for some time now.
‘‘But now there are similarities between the tests on the players, and the staff must search strongly for the source. But the substance is not in food. We know that.
‘‘The players who have played for Holland this season must be checked as soon as possible. That is because they do not know what substances are in their bodies at the moment and whether or not they will be tested positive.
‘‘The Dutch international players are all really worried about these developments. We know we haven’t been put in jeopardy deliberately by our FA and we certainly trust them. But there is something seriously wrong with this situation.’’