Northamptonshire chief executive David Smith has apologised for criticising the Old Trafford pitch.
Smith was disappointed with the surface during Northamptonshire's loss to Lancashire inside just two days in a County Championship contest last month.
He said at the time: "Was this a good wicket? Was it a fair contest between bat and ball? No.
"This should have been a showcase Division Two game between the top two teams, and it was not allowed to be."
Pitch inspector Jack Birkenshaw confirmed that the surface was satisfactory and the ECB "formally reprimanded" Northamptonshire and "reminded them of their responsibilities."
Northamptonshire are currently top of the second division of the County Championship.