The head of Senate Republicans' 2010 election efforts said it is too soon to make an endorsment in the Pennsylvania Republican primary, despite only one major candidate currently being in the race.

National Republican Senatorial Committee (NRSC) Chairman John CornynJohn CornynTrump launches all-out assault on Mueller probe Senators who have felt McCain's wrath talk of their respect for him Senate heads to new healthcare vote with no clear plan MORE (R-Texas) told a Christian Science Monitor breakfast that it "would be premature" to endorse former Rep. Pat Toomey (R) in the state's Republican primary.

"That primary is still forming and there are other people looking at the race," Cornyn said.

National Republicans have been fretting about their chances to keep the seat since Sen. Arlen Specter switched parties to seek reelection as a Democrat. Cornyn had sought to recruit former Gov. Tom Ridge (R) into the race, but he declined.

Cornyn also talked up recruits in other swing states ahead of the 2010 midterm elections.

The NRSC chair said former N.Y. Gov. George Pataki (R) is "thinking about" entering the New York Senate race, and that contingency plans are in place should Rep. Mark Kirk (R) decline to run for Senate in Illinois.