Among those considering a run at the five-term Republican is Chris Matthews, host of MSNBC's "Hardball" and a former Democratic staffer in Washington, the Allentown (Pa.) Morning Call reported Wednesday. Matthews, who declined to comment, reportedly has been considering a Senate run for months and has met with Pennsylvania Democrats to discuss his prospects.

Others believed to be considering taking on Specter are U.S. Reps. Joe Sestak and Allyson Schwartz, and state Rep. Josh Shapiro, the Morning Call said.

''There are a lot of compelling reasons why serious Democrats would aspire to run in 2010,'' Pennsylvania Democratic Committee Chairman T.J. Rooney said. ''You look at what has gone on in this state in the past six or seven years and you think nothing is out of reach."

Since 2002, the newspaper said, Pennsylvania Democrats claimed the governor's mansion, upended Rick Santorum, once the Senate's No. 3 Republican, and picked up five U.S. House seats.