The 33-year-old midfielder has played a key role in Barca's dominance over recent years, winning seven league titles and the UEFA Champions League three times with the club.
Rosell, who presented the Spain international with the Barca Jugadors award for fair play on Thursday, claims Xavi, along with Lionel Messi, Andres Iniesta and Sergio Busquets, have been the main contributors to Barca's renowned style.
However, Rosell explained he is not sure as to whether tiki-taka could continue once Xavi leaves the Camp Nou.
"I have always said that Xavi, Andres and Leo, with help from Busquets, were the inventors of tiki-taka," he said.
"Tiki-taka is not a philosophy that Barca have had since its foundation.
"Tiki-taka was invented by these three, plus Busquets. Tiki-taka is Xavi’s registered trademark. The day he is not here I do not know if we will be able to continue with it."
Xavi has featured 14 times in La Liga this season, scoring twice, as he seeks to help Barca to a second straight league title.
Rosell is in no doubt that Xavi is the best player Spain has ever produced.
"With his numbers there is no discussion," Rosell said.
"(Xavi) is the best player in Spanish football history."
