The burly 31-year-old may not, however, be allowed to play in the Argentine championship until next season having already turned out for Velez Sarsfield in the current campaign.
Boca coach Julio Cesar Falcioni still wanted Silva, who helped his Banfield team win the Argentine Apertura for their first league title in 2009, to strengthen his squad for the South American Libertadores Cup.
"If I have to go six months without playing the championship, we'll wait," the shaven-headed Silva told reporters at Ezeiza International Airport on his arrival in Buenos Aires.
"I've no idea if I'll be able to play the [Clausura] championship. In principle it's going to be the Libertadores."
Former Boca and Argentina striker Martin Palermo, who retired in June, said recently that Silva was a perfect fit as centre-forward in the team with whom he won a string of titles including two Libertadores and one Intercontinental Cup.
"That Palermo, such an idol, should have said I'm the ideal number nine for Boca is motivating," Silva said.
He said he had not settled at Fiorentina partly due to a change of coach in November.
"I could have stayed to fight for [a place] but I preferred Boca," said Silva, who won a Uruguayan league title with Nacional in 2002 and the Argentine Clausura with Velez last June. He has also played for clubs in Brazil, Portugal and Germany.
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