Italian Players' Association (AIC) president Damiano Tommasi has threatened to delay the start of the new Serie A season unless the Italian Football League signs a new collective agreement.
The old agreement ran out a year ago and twice last season player strikes were planned before being called off as negotiations progressed.
But Tommasi, a former Italy and Roma midfielder, says the kick-off on August 27 will be postponed unless the agreement is signed by all parties.
"Yes, the league kick-off is at risk," he told SkySport24.
"The collective agreement needs to be signed and that needs to happen before the season can start.
"Even the Italian Football Federation (Figc) president (Giancarlo Abete) has said it.
"It would be hard for the players to not take to the pitch but we need their rights to be put in black and white, and it's not an economic question.
"The players are united in their intent, I've visited 90 percent of Serie A teams."
The original dispute was over the rights of clubs to force certain conditions, including transfers, on players approaching the end of their contracts.
All points have been agreed accept one relating to players no longer part of the first team squads, with the Football League asking for greater flexibility over the article.
Tommasi's predecessor Sergio Campana signed the agreement last season but the Football League has yet to put pen to paper.
"We've found an agreement and underlined it. I keep hearing that we're very close, but the little that's missing from the League's side never arrives," said Tommasi.
"This has been dragging on since last season. In the previous months we decided not to strike while the league was ongoing but this time if we don't get a conclusion it won't begin."