Updated: 3:19 p.m. | Ret. Air Force Colonel Martha McSally filed federal paperwork on Monday to once again challenge Democratic Rep. Ron Barber in Arizona’s 2nd District.

Republicans view the seat as one of their best pickup opportunities this cycle, as Barber is considered one of the most vulnerable incumbents of 2014.

Barber defeated McSally, a Republican, by less than 1 point in 2012 in a district that Mitt Romney won with 50 percent. Speculation over whether McSally would want a rematch began almost immediately after election officials declared Barber the winner.

CQ Roll Call reported in April that McSally was leaning toward another round with Barber. Prior to running for Congress, Barber served as a top aide to former Rep. Gabrielle Giffords, D-Ariz., who was seriously injured in a shooting spree that ended the congresswoman’s career.

Rothenberg Political Report/Roll Call rates this race a pure Toss-Up.

Update | “I’ve received very positive encouragement to run again from the Southern Arizona community and am considering exploring a candidacy, although I have not made a final decision,” McSally said in a written statement. “Right now we are all praying for the victims of the fire raging in Arizona. In the weeks ahead, I’ll be making some decisions about running in 2014.”