RICHMOND, Va. — Prosecutors have more leverage against Michael Vick now that his remaining two co-defendants decided to plead guilty while he has maintained his innocence in a federal dogfighting conspiracy case.

"He's hanging out there by himself, and that's a very uncomfortable place to be," said Anne Coughlin, a University of Virginia School of Law professor and expert on criminal procedure.

A spokesman for Vick's lawyers declined comment Tuesday on media reports quoting unnamed sources as saying prosecutors and the defense were negotiating a possible plea agreement, and that Vick faced a Friday deadline to either accept a deal or face additional charges.

But the spokesman, Collins R. Spencer III, didn't rule out the possibility of an announcement by the Vick team sometime this week, probably in Richmond.