Updated, 4:56 p.m.

Rep. Trent Franks (R-Ariz.) has announced he will not run for Senate, despite openly discussing the possibility for weeks.

Franks had been preparing to challenge Rep. Jeff Flake (R-Ariz.) in a GOP primary for the seat left open by Sen. Jon Kyl’s retirement.

“After diligently and prayerfully trying to consider every aspect a potential Senate bid would entail, I have sincerely concluded that mounting a Senate bid at this time would not be what is best for my family, nor what would best allow me to serve my country at this critical time in her history,” Franks said in a statement released from his Congressional office.

The move means Flake will avoid a competitive GOP primary challenge from his House colleague.

“Trent is a good friend and I’m glad I won’t have to face off against him in a campaign,” Flake said in a statement after an Arizona television reporter broke the news.

Franks’ move took political observers by surprise.

One Arizona Republican source mused that it could be an April Fool’s joke. “As of this morning his staff was adding staging at his location for the press conference,” the source said.

Democrats do not have a candidate. Roll Call Politics rates this race Leans Republican.