Schopp has emerged as the preferred candidate as Barnsley look to replace Valerien Ismael who has joined Championship rivals West Bromwich Albion.
As was the case with Ismael, Schopp has a buyout clause meaning Hartberg will be powerless to stop the Austrian moving if talks are productive.
Hartberg are expecting Schopp back in the country on Tuesday but sporting director Erich Korherr says the search for his successor has not yet started.
"He'll be back on Tuesday. Then we'll see,” said Korherr.
“We will find a solution. (Starting to look for a replacement) wouldn't be fair to Markus.”
Hartberg travelled to Schilleiten, described as an Austrian "sport resort castle" on Monday to prepare for the new season. They had expected their 47-year-old coach to be in charge for it, having only signed a one-year contract extension in May, but the time it has taken West Brom to replace Sam Allardyce has had a knock-on effect.
Schopp is a former coach of Sturm Graz's second team, and had a brief spell as first-team caretakerr head coach in 2013. He worked as an assistant and analyst at St Polten before moving to Hartberg in 2018.
During his playing career the midfielder played for two Red Bull clubs - Salzburg and New York. Barnsley and their American chief executive Dane Murphy are big fans of the Red Bull set-up which has been prodigious in its production of top-quality coaches, including Barnsley's last Austrian coach, Gerhard Sturber, who left them for New York.
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