put the blocks on
put the blocks on (something)
To prevent something from happening or proceeding; to create or place an obstruction to something. An allusion to placing blocks of wood or steel in front of a vehicle's wheels to keep it from rolling forward or backward. It looks like the CEO put the blocks on the deal at the last minute after pressure was put on him by consumer advocates.
put the blocks onprevent from proceeding.
A block of wood or other material placed in front of a wheel prevents forward movement.