Rep. Trent Franks is considering a run for retiring Sen. Jon Kyl’s seat in Arizona, his spokeswoman confirmed Monday evening, expanding the field of potential candidates.

“Congressman Franks is indeed exploring that option. He’s not made any final decisions yet,” said Bethany Haley, spokeswoman for the Arizona Republican.

Rep. Jeff Flake (R-Ariz.) formally announced his candidacy during a news conference earlier Monday in Phoenix and was promptly endorsed by the conservative Club for Growth.

Meanwhile, according to a GOP strategist based in the Grand Canyon State, Arizona Corporation Commission Chairman Gary Pierce (R) is also considering a bid to succeed Kyl (R). The Senate Minority Whip announced Thursday that he would not run for re-election in 2012.