In a conference call with reporters, Clinton Senior Adviser Harold Ickes clarified their position on Michigan -- they don't want the 55 "uncommitted" delegates to go to Obama (his name did not appear on the ballot in Michigan).
There have been reports that some of the uncommitted delegates in Michigan already selected are union supporters of Clinton. This solution, unsurprisingly, would make it much harder for Obama to clinch a pledged delegate majority.
Last week, the Clinton campaign was agnostic on the issue -- but they seem to ratcheting up the noise, or at least their negotiating position.
Ickes also mentions that the co-chairs of the Rules and Bylaws Committee -- which will rule on Florida and Michigan on May 31 -- have been holding "informal meetings" with leaders of both of the campaigns.
UPDATE: Wolfson says that most -- if not -- all of the uncommitted delegates would likely go for Obama.
(h/t Ben Smith)