Gross, who manages the world’s biggest bond fund and has spent recent months jawboning about the dangers of U.S. debt, has placed a $7 billion bet against Treasury bonds, according to the latest statistics released by his Pimco Total Return fund.

Gross made a splash last month by selling all the big bond fund’s Treasury holdings and calling the federal budget a Greek tragedy in the making. Now he has gone one better, leaving the $236 billion fund with a short position in U.S government debt for the first time since February 2009 – and putting a third of the fund’s assets in cash.

The last time Gross was short Treasuries, he was also short cash, in a timely bet that the U.S. economy and financial markets would rebound from their meltdown lows. This time, however, he appears to be expecting something altogether different.

His fund is holding a staggering $73 billion of cash, in an apparent bet that the market recovery is on borrowed time. Gross’ wager against Treasury debt was first reported on ZeroHedge.

The bet comes at a time when the government is struggling, to put it mildly, to get its budgetary act together. Congress and the White House agreed Friday to $38 billion in spending cuts, narrowly averting a government shutdown. But the agreement hardly won much of a reprieve: all eyes will now turn to the fight over raising the debt ceiling that the United States is expected to hit next month.

Gross hasn’t been optimistic that our political class will avert a crisis. His Greek tragedy commentary reasons that unfunded U.S. entitlement spending amounts to five times gross domestic product – a bigger debt burden than the one in bailed-out Greece. When you consider the government came within two hours of a shutdown Friday when the sides were just a few billion apart, it is easy to be pessimistic.

Massive federal spending and full-throated political posturing is certainly a toxic combination, and the news that Gross is wagering U.S. rates will go higher won’t ease the pressure on the Treasury market. The yield on the 10-year Treasury bond has risen to a recent 3.59% from a 2011 low of 3.22% on March 16.

Treasury securities aren’t the only bonds Gross is betting against. Gross cut the Total Return Fund’s holdings of mortgage securities to 28% of assets from 34% — putting him on the other side of a bet that many investors, including the guys who run AIG (AIG),  are making for a further recovery in that asset class.

And as Gross has made clear, it isn’t just the bond market that he expects to take a hit in coming months as the Federal Reserve’s quantitative easing winds down. It is not very hard to find people who expect to see the stock market take its lumps too.

All the same, it is clear that it wouldn’t take much of a dip in Treasury prices to bring Pimco back to the lot to start kicking the tires again. In spite of his posturing about bond market turkey shoots and the like, Gross told Bloomberg last month he believes U.S. economic growth dictates that the 10-year Treasury should trade “with a 4% type of yield.” That was before everyone started downgrading their U.S. growth forecasts, mind you.

In any case, a half-point increase in Treasury rates hardly sounds like the sort of disaster Gross has been invoking. If Treasuries do sell off in coming weeks, don’t be shocked if Pimco’s next report shows it nibbling again at this tepid buffet.

Also on Fortune.com:

• Gross calls U.S. budget a Greek tragedy
• Gross wants Treasury yields north of 4%
• Gross calls for bond market turkey shoot

Follow me on Twitter @ColinCBarr.