put the blocks on

put the blocks on (something)

To prevent something from happening or proceeding; to create or throw up an obstruction to something. An allusion to placing a large block of wood or steel in front of a wheel 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.
See also: block, on, put

put the blocks on

prevent from proceeding.
A block of wood or other material placed in front of a wheel prevents forward movement.
See also: block, on, put