put or go on the block. Offer for sale, as in These paintings will all be put on the block. This usage alludes to the auction block, the platform from which the auctioneer sells, so called since the mid-1800s.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.