London: Derbyshire sacked head of cricket John Morris and assistant first-team coach Andy Brown midway through their County Championship match at home to Essex, the Midlands club said on Thursday.
Both the contracts of former Derbyshire and England batsman Morris and Brown were due to expire later this year but club chairman Chris Grant said: "After careful consideration, it has been decided not to renew their contracts and both will be released from performing their duties immediately."
Derbyshire's opening four Second Division Championship games have yielded just one win and one draw with two defeats.
But they lead their group in the county 40-over competition following wins against Sussex, Yorkshire and Worcestershire.
Grant added: "I have spoken to the club captain Luke Sutton, academy director Karl Krikken and bowling coach Steffan Jones and these individuals, together with committee member Tony Borrington, will oversee the running of the first team for the remainder of the season.
"The positions of lead physiotherapist James Pipe, strength and conditioning coach Luke Storey and second XI coach AJ Harris are unaffected.
"I would like to thank both John and Andy for their efforts while they have been employed by Derbyshire and wish them the very best in their future endeavours."