Pennsylvania Sen. Arlen Specter’s double-digit lead in the 2010 general election appears to be slipping, according to new poll results released Thursday.

Specter, who only recently switched to the Democratic party, led former Rep. Pat Toomey (R), 46 percent to 37 percent, in a new Quinnipiac University survey of Keystone State voters. The 9-point margin is less than half of the lead that Specter had over Toomey in a May 4 Quinnipiac poll that was conducted just days after the six-term Senator announced he would switch parties to run as a Democrat in 2010. He led Toomey by 20 points in that survey.

The poll also showed Specter leading his likely Democratic primary opponent, Rep. Joe Sestak, 50 percent to 21 percent. Sestak’s office confirmed Wednesday that he plans to get into the race, much to the dismay of the White House and other Democratic Party leaders, who have pledged to back Specter next year.

Also in the poll, Toomey led a potential Republican primary opponent, Rep. Jim Gerlach, 38 percent to 10 percent. Unlike Toomey, Gerlach has not announced a bid for the seat, but he has stated he is interested in running for the GOP nomination for either Senate or governor.

The poll took the opinion of 1,191 Keystone State registered voters from May 20 to May 26 and had a margin of error of 2.8 points for the general election match-up. There were 517 registered Republican voters and 561 registered Democratic voters in the survey.

The margin of error for the Democratic primary portion of the survey was 4.1 points, and for the GOP primary it was 4.3 points.