Houston concern over winger
Manager Peter Houston is concerned that winger Gary Mackay-Steven will remain sidelined for longer than originally anticipated.
The 22-year-old was expected to be ruled out for up to six weeks after requiring a routine knee operation at the end of August.
He had previously been playing through the pain barrier until it was decided he should undergo surgery to finally resolve the problem.
In his absence United's form has seriously faltered with five league games without a win seeing them slump towards the bottom of the table.
"Gary is taking time," Houston told the Dundee Courier. "He's not anywhere near ready to join back in training so he is still doing the rehabilitation. A couple of times the knee has swelled up a bit and then it's gone down again so we're just being gentle with him."