"Republicans are squeezed between the tea party on the extreme end and [Gov.] Corbett and his anti-woman, anti-public education stance on the moderate end," Platt said.
He said John Kane (no relation to Attorney General Kathleen Kane), business manager of Plumbers' Union Local 690, planned to run for the seat.
But Sen. Dominic Pileggi (R., Delaware) said he was confident the Republican Party, which still holds the registration advantage in the district, could retain the seat.
"It's a winnable district for Republicans, and we intend to defend the seat with all the resources and talent we can bring to bear," Pileggi said Friday.
Pileggi said Rep. Nick Miccarelli (R., Delaware) and Delaware County Council Chairman Tom McGarrigle were among the Republicans considering running next year. Also being named as a possible contender is the county's executive director, Marianne Grace.
Members of the state Senate are elected to four-year, staggered terms, with elections for half of the members held every two years.
Up for election next year are 15 Republican-held seats and 10 Democratic seats.
Erickson was elected in 2001 in a special election for the 26th District seat held at the time by Sen. Joe Loeper, who was sent to federal prison on obstruction charges.
Erickson had previously served as executive director of Delaware County and as a member of the Delaware County Council and was a regional administrator for the Environmental Protection Agency.
"He certainly has an extraordinary record of public service," Pileggi said. "He is a great advocate for constituents in the Senate and a leader on environmental and health-care issues in our caucus."
Erickson did not return a call seeking comment.
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