Even with "sterilisation" as proposed, newly printed money remains in the system to eventually circulate. The reasoning offered in "Sterilized bond buying an option in Fed arsenal" is not easy to understand. The purpose of quantitative easing (money printing) is to create liquidity - that is, to inject more money into the financial system to make money easier to come by. If the newly printed money's inflationary risk is properly "sterilised" then that money wouldn't enter wider circulation, which would defeat the purpose of printing it.
The real intent is to circulate that newly printed money in the wider financial system.
It is not clear how the newly printed money would be circulated between the Federal Reserve, the Treasury and other institutions. If none leaked out there would be no reason to print the new money in the first place.
Newly printed money might be sterilised by depositing that money with the US Treasury, by buying US treasuries, which is effectively lending the newly printed money to the US government, which is already deeply in debt. It is possible that that newly printed money would be released by the Treasury to enter circulation through continued US government deficit spending, thereby achieving its ostensible purpose of injecting money into the wider financial system.
It is in this way that the US government is able to print money for itself, without the strict fiscal discipline being demanded of Greece; and why the majority of congress regularly votes to repeatedly raise their "helium" federal debt ceiling. (Or might the ceiling be of hydrogen?)
The Fed is not left with many alternatives other than to print more new money, essentially to support institutions which have borrowed too much money.
One possible intent of the Fed's announcement, and the seemingly confused media articles, would be to create the false perception that money could be printed without inflationary consequences. This is the "spin", or propaganda, which one must see through in order to make wiser investment decisions.
I acknowledge The Wall Street Journal's "Sterilized bond buying an option in Fed arsenal".