Chester County Recorder of Deeds Ryan Costello (R) announced Monday that he is dropping out of the open-seat race in Pennsyvania’s 6th district next year. Costello’s departure from the race leaves four other Republicans vying to replace Rep. Jim Gerlach (R-Pa.), who is running for governor in 2010.

State Rep. Curt Schroder and businessman Steven Welch are now the leading contenders in the GOP primary. Welch had been preparing to run in the open-seat race in the 7th district but switched this fall to run in the 6th instead. Many GOP insiders view Welch as their strongest possible candidate due in part to his ability to put personal resources into the contest. He has loaned his campaign at least $500,000 so far.