On 9 November 2007, during the 2007–08 season, Mattock signed a new three-year contract with Leicester. The club rejected a bid from an unnamed Premier League club for Mattock on 14 January 2008 (later revealed to be West Ham United). Following Leicester's relegation in the 2007–08 season, Aston Villa became interested in Mattock and then-teammate Richard Stearman. While Stearman left for Wolves in the July transfer window, Mattock remained at the club for another year. He did, however, hand in a transfer request during pre-season, but was unable to secure a deal with any club.