The 2012 season saw injury restrict Kirby to just nine first-class matches and saw him take 24 wickets at an average of just over 30. Prior to the 2013 season, Kirby was included in the MCC squad for the Champion County fixture, for the fourth time in his career. The season again saw Kirby limited to just 10 first-class matches due to injury despite this he took 26 wickets at an average of 35.11. The end of the 2013 season saw Kirby sign a new contract of undisclosed length with Somerset.