Reading pair Sean Morrison and Jordan Obita have both signed new contracts at the Madejski Stadium.
Ipswich defender Aaron Cresswell has signed a two-year extension to his contract.
Negredo, who scored 25 Primera Division goals last season, is set to join the Barclays Premier League runners-up for a reported 23million euro fee after Del Nido revealed the Andalusian outfit are on the verge of ratifying the sale.
He told Sevilla's official website: "We are about to close on the sale of the player and, if everything goes normally and everything is signed, he will soon say goodbye to the Ramon Sanchez Pizjuan.
"Manchester City are buying a great player, the top-scoring Spaniard in La Liga. This is a big deal for Sevilla, the second most important in our history after we sold (now-Barcelona full-back) Daniel Alves, and the player will sign the contract of his life.
"Everyone should be happy; it is a great deal for all three parties."
Should the deal go through, Negredo will follow winger Jesus Navas from Seville to Manchester, with Brazilian midfielder Fernandinho representing City boss Manuel Pellegrini's other summer signing to date.