Illia Zabarnyi and Dean Huijsen left for Paris Saint-Germain and Real Madrid last summer and Marcos Senesi has since moved to Tottenham over the past month as Bournemouth’s defence is raided.
Silva, 22 years old is a centre-back who favours the right side and will become a brand-new addition for manager Marco Rose who replace Andoni Iraola this summer as he left to join Liverpool.
Manchester United, Chelsea and Liverpool were said to be interested the young defender but it is the Cherries who have snapped him up for a cut price deal in what is an impressive piece of business.
Silva is expected to become Bournemouth's second signing of the summer after the arrival of striker Alvaro Rodriguez from Elche in a deal worth up to £25.7M.
Silva should thrive under Rose
Speaking to Joao Nuno Fonseca, Silva's coach during his days with Benfica's development team, he explained that working under Rose in the English top flight will be a major step up.
"I think it will work fantastically because of the way Antonio reads situations," says Fonseca. "Marco will demand anticipation, a defender who looks for forward passes that break the lines and find those spaces in behind. Antonio will adapt very quickly.
"Antonio is very capable and is completely ready to play in the Premier League. But it will be a different challenge for him. The challenge in England is week by week, not just waiting for the European games like he could at Benfica. The focus must be there."
The deal for Silva comes after he led Benfica to a 5-0 victory over St. Gallen in the second round of Europa League qualifying last night.