Since retiring from professional cricket Middlebrook has become an umpire, standing in first-class matches from the 2017 season onwards.

Middlebrook joined Northamptonshire at the start of the 2010 season,[3] where he regularly opened the batting.

In January 2010, Middlebrook along with new team-mate David Sales, was picked to represent the Marylebone Cricket Club (MCC) against Durham in Abu Dhabi.

[4] Despite being Northants leading runscorer in the 2014 season, Middlebrook was released following the club's relegation to Division Two of the County Championship.

[5] He was signed by Yorkshire on a short-term contract as cover for Adil Rashid whilst the leg-spinner was part of England's tour party in the West Indies.