The 26-year-old ended last season as the Serie A top goal scorer with 25 goals in his 36 league games, helping his side to a third-placed finish.
According to Gazzetta dello Sport, he will now make the shock move to Saudi Arabia after the two clubs agreed to a massive €68 million deal.
It’s expected to be announced in the coming days with final documents are pending, and minor payment terms and bonuses needing to be resolved.
Retegui will put pen to paper on a four-year contract worth €16m with another €4m in bonuses, which represents a huge increase from his current deal.