Sunderland have completed the signing of Celtic right-back Adam Matthews for a fee of £2million.
Diego Poyet is determined to establish himself in Slaven Bilic's West Ham side this season and avoid another loan spell.
The Turkey international moved to Spain from Galatasaray in 2011, helping Atletico win the Europa League in his first season and the Copa del Rey last term.
The 26-year-old told the club's website: "I feel very happy to have extended my contract with Atletico.
"After two years with Atletico I I feel like part of the family which is the club. If I'm so happy at the club, its because my team-mates are so strong and we're all in this together."