Striker Pazzini and defender Zapata have arrived after the departures of Zlatan Ibrahimovic and Thiago Silva to Paris Saint-Germain as seemingly direct replacements.
Yepes, who signed a new deal with Milan earlier this year, has spoken of the strengths of his new teammates.
"Pazzini is an out-and-out striker that maybe we've been missing," Goal.com quotes Yepes as saying. "So let's hope that he can settle in well and do those things that he was doing at Sampdoria, and that he did for Inter as well.
"I think he'll be looking for a bit of revenge and maybe Milan can give him that chance.
"Zapata knows the Italian league well. He knows the environment and he knows what the situation is here at Milan. He's a very physical player, very fast and, if we're lucky, he'll be able to do the things here that he did at Udinese."
Yepes has made 24 league appearances for Milan.