Before they were morphed and twisted out of shape by cable news networks, the words 'liberal' and 'progressive' were not overlapping concepts. Traditionally progressives were the reformers who wanted to improve conditions for working people through the established political process. These folks had there golden era during the first two decades of the Twentieth Century lead by a corps of social advocates and muckrakers who took on the horrible conditions of anyone who wasn't rich or a capitalist.
Progressive were at odds from the radicals, anarchists and syndicalists who just wanted to literally blow the whole thing up.
Traditional liberals are those who try to get government out of everyone's lives. They want to say and do what they want without governement interference. The folks would be the ones in opposition to the big state type of government.
John Podesta, who headed the transition for Barack Obama and is renovating the concept of progessivism, wrote a book last year call "The Power of Progress" which outlines the differences.
Using these definitions, Podesta describes the Obama Administration as progressive. So far he doesn't appear to be a Liberal.
Take that Rush Limbaugh!