"Sampdoria announce that the relationship with coach Luigi Del Neri will not continue in the 2010/11 season," a club statement said.
Media reports quoted Samp owner Riccardo Garrone as saying 59-year-old Del Neri, famous for his trademark glasses and prominent chin, was almost certainly going to Juve.
In what should have been a joyous week for Samp after finishing fourth in the league and securing only their second berth in Europe's top competition, the Genoa club now have to find a new coach and sporting director.
Beppe Marotta has quit as Samp sporting director to take up the same position at Juve.
"With Juventus there is a verbal agreement," Marotta told Italian radio. "My passage to Juve has not been made official, it's up to the Juve directors to do that, but I will limit myself to say that Juve must return to being competitive."
Juve, who finished seventh this season and are saying goodbye to interim coach Alberto Zaccheroni as they rebuild completely, have made no comment.
The twice European champions are Italy's most successful domestic club and the best-supported, hence they still have immense pulling power despite enduring a miserable campaign.
Media reports had linked Juve with Liverpool's Rafael Benitez ever since Ciro Ferrara was sacked in January but former AS Roma, Porto and Atalanta coach Del Neri became the bookmakers' favourite last week.
Samp fans, who celebrated in their thousands as the team toured Genoa by open top bus on Sunday, fear Marotta could take top players such as striker Giampaolo Pazzini with him.
Juve were demoted from Serie A in 2006 after a match-fixing scandal but bounced straight back and finished third and second in the top-flight before transfer flops and injuries ruined the recently ended campaign.
