(CNN) A freshman Democrat, who strongly opposes House Democrats' impeachment of President Donald Trump, is expected to switch to the Republican Party and is telling colleagues his intentions, according to two sources.

Rep. Jeff Van Drew is considering the switch as he struggles in New Jersey politics. Internal polling has shown he was losing major support from Democrats in the district, Democratic sources told CNN on Saturday. Switching parties would allow Van Drew to avoid a Democratic primary challenge for his seat.

New Jersey Gov. Phil Murphy on Saturday blasted the change, saying Van Drew is "willing to enable Donald Trump just to try to salvage his own election."

"Betraying our values by siding with Donald Trump is the final straw and made it impossible for him to continue being supported by our party, as grassroots activists, local party leaders in his district, and I have made clear in recent weeks," Murphy, a Democrat, said in a statement. "This party switch is cynical and desperate, and I am confident that a Democrat who shares the values and priorities of our Democratic Party will hold this seat."

A senior Republican source also confirmed to CNN on Saturday that Van Drew is expected to switch parties. He has told his staff and met with Trump, according to the source.

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