Andrea Della Valle has hailed Giuseppe Rossi's return to Italy as a "gift for Italian football".
Fiorentina completed the signing of the Villarreal striker on Friday for a fee believed to be in the region of just over €9m [£7.3m], on a four-and-a-half-year-deal.
"We are pleased to have brought a great player like Rossi back to Italy, It is not just a great moment for our fans, but a gift for all of Italian football," Della Valle told reporters.
"This move is also an important part of our project here that is making good progress. Rossi is one of the few talents still available."
Rossi is currently injured after damaging the same knee ligament twice in one year and is not expected to return until March.
"In around a month he will start training with the rest of the team. He will have to take it slowly though," he added.
The player himself has thanked Villarreal for their support on his personal Twitter account, after bringing an end to his six-year stay at the club.
"I want to thank Villarreal as they were more than a team for me, they were a family."