The proposal was revealed by a former Polish Foreign Minister, Radoslaw Sikorski. Mr Sikorski stated that Putin described the Ukraine as an “artificial country”. Current Ukrainian territory also includes areas which were formerly part of Poland before World War 2, notably Lwow, known as Liviv, in the northern Ukraine. This area later became part of the Soviet Union. It's unclear if this was the actual proposal made to Poland.
What’s really strange about it is the idea of Russia doing any sort of deal with Poland. These two nations have spent a lot of time fighting each other, since the Grand Duchy of Warsaw, in fact, and they’re not historically what you’d call cheerful neighbors. Catherine the Great and Frederick the Great destroyed the former Poland by partitioning it in the late 18th century.
In 1921, the Poles drove out an invading Soviet army and set up what is now the basis of modern Poland. In 1939, the Soviets partitioned Poland with Hitler, which didn’t exactly endear them to the Poles, past or present. Russia also more or less occupied Poland until the breakup of the Warsaw Pact and the collapse of the Soviet Union.
Chummy, they are not, and if the idea was to gain some credibility for the partition of the Ukraine with Polish support, it was never more than a very long shot. The idea doesn’t have a lot of real traction. Polish support for a breakup of the Ukraine would have been extremely unpopular with the EU, a real economic own goal. Moscow wouldn’t have needed to be told that, so why make a proposal that couldn’t fly at all?
Sikorski’s belated efforts to downplay the report may mean that a discussion of territorial issues has received tabloid treatment and been drastically overblown. This may be hype, badly orchestrated hype, at that. What it’s not likely to be is an accurate depiction of Russian foreign policy.