Republican Rep. Ryan Costello of Pennsylvania is considering retirement, several state and national officials in GOP politics have told ABC News, a move that would boost Democratic hopes in their quest to retake control of the House.

Costello’s district was one that was most deeply affected when the state Supreme Court redrew the congressional map.

His 6th Congressional District was transformed from one that Hillary Clinton won by one point in 2016 to one she would have won by nine points under the new lines.

The boundaries shifted to include all of Chester County and the city of Reading, which could add to the Democratic voting base.

“It’s difficult in 2018 to win Chester County,” one local Republican official said of the new map.

Republicans have speculated that Costello, a 41-year-old attorney, could preserve his future political options by retiring and returning to elected office in a year more favorable to the GOP, sources tell ABC News.

Costello has not said he is retiring and his office and campaign did not respond to ABC News' multiple requests for comment. The lawmaker has held several signing events for his candidate petition, including one on Monday night in his district.

Democrats were already excited about this race and their candidate Chrissy Houlahan, an Air Force veteran who was endorsed by former Vice President Joe Biden on Thursday.

Costello’s retirement could significantly boost their chances of taking this district and putting them on their way to winning the 24 seats they need to take control of the lower chamber.

The new Pennsylvania map is expected to give Democrats a chance to capture three to five House seats in their quest to retake the chamber. State Republicans have challenged the map in court in order to keep the old lines but no final legal decision has been rendered.

Republicans face a ticking clock. The petition deadline to run for the seat is March 20th, which is less than a week away and doesn’t give a candidate a lot of time to gather the necessary signatures to run.

But the GOP seems to be hedging their bets.

One local Republican in Chester County told ABC News that they were approached to run for the seat. They declined to do so.

One name that has come up among local Republicans as a possible candidate is Chester County Commissioner Michelle Kichline.

Ironically, Kichline replaced Costello in the county commissioner’s office in 2014. The daughter of Hungarian immigrants, she also served on Tredyffrin Township’s Board of Supervisors.

Kichline’s office did not respond to multiple requests for comment.

During Tuesday's special election in Pennsylvania’s 18th Congressional District, Democrat Conor Lamb performed strongly in the deep red district which Donald Trump won by 20 points in 2016.

Many saw Lamb’s strong performance as a warning to Republicans in tough races that Democratic enthusiasm is higher and voter turnout is expected to be huge.

Republican leaders in a meeting with GOP House members on Wednesday warned the party faithful it was time to get serious about their reelection campaigns.

Pennsylvania’s GOP House delegation is losing a lot of incumbents this year.

Rep. Tim Murphy resigned after a scandal. Rep. Lou Barletta is running for Senate. And Reps. Bill Shuster, Charlie Dent and Patrick Meehan are retiring.