Dundee United say they are expecting to hear more about Rodney Sneijder's health this midweek.
The midfielder returned to the Netherlands before Saturday's 2-0 Premiership win over Motherwell.
United manager Jackie McNamara reiterated what he said at the weekend - that the 24-year-old new signing has a viral infection.
"He will be having further medical tests today and tomorrow in his homeland," McNamara told BBC Scotland.
"He took a viral infection last Wednesday night and done some tests in hospital and went back home on Thursday with his father to Holland.
"I know he's doing some more today and tomorrow and hopefully we have some news tomorrow or Wednesday.
"I was speaking to him on Saturday night and hopefully we can get home back as soon as possible."