With the hypothetical possibility of a new MSNBC show at 10pmET, each guest hosting spot gets extra scrutiny.

This was the case with radio host Ed Schultz, who filled in for David Shuster on 1600 Pennsylvania Avenue yesterday. The New York Observer’s Felix Gillette writes the news, “touched off a fresh set of rumors among MSNBC staffers that the network’s president Phil Griffin might be grooming Mr. Schultz to join the channel on a fulltime basis.”

But a spokesperson shot it down: “Ed is a regular on 1600. He’s filling in for David tonight, while David fills in for Keith [Olbermann]. It’s as simple as that.”

Schultz got in a shot at his competition during yesterday’s show, describing the temperature during a report as “a high of Glenn Beck‘s IQ — zero!”

Schultz was part of our original 10pm poll and received 5% of the vote. Voting is still open for our new MSNBC 10pm poll.

Click continued to see the Beck comment…