The Italy youth international is expected to finalise a transfer to the Serie A leaders in the coming days after a deal was agreed between the clubs.
The 19-year-old winger, who was also linked with Napoli and Chelsea, was pictured arriving at Juve's J Medical centre on Thursday.
Ascoli director Ivan Lanni stated last week that they expected the deal with Juve to go through, with Orsolini set to be loaned back for the remainder of the season.
"An agreement has been reached with Juventus," he told PicenoTime. "We couldn't say much, but there's always been a desire to close things out with Juve.
"The process is very complex. There's a basic deal, variables and talks related to various players. What's certain is that Orsolini will remain with Ascoli until the end of the season."