Sen. Johnny Isakson (R-Ga.) greets GOP Senate candidate David Perdue at the Dekalb Peachtree Airport on Nov. 3, in Atlanta. (AP/John Bazemore)

Sen. Johnny Isakson (R-Ga.) plans to formally announce plans to run for reelection on Monday in Georgia, according to an aide.

Isakson will make the announcement on Monday at 11 a.m. at the State Capitol and will be joined by Republican Gov. Nathan Deal, Lt. Gov. Casey Cagle and GOP state lawmakers, according to his spokeswoman, Marie Gordon.

Isakson, 69, is in his second term. He was first elected to the House in 1999 to replace former Speaker Newt Gingrich (R-Ga.). His formal announcement will come less than two weeks after Election Day, when Republican David Perdue won the seat of retiring Sen. Saxby Chambliss (R-Ga.).

Isakson's early announcement is likely designed to keep the field clear of any potential GOP challengers. The race to succeed Chambliss started as a seven-way contest and included a runoff between Perdue and Rep. Jack Kingston (R-Ga.).

Georgia Democrats were initially buoyed by the candidacy of Michelle Nunn, which resulted in weeks of public polling suggesting the race was close and might be forced into a runoff, though it resulted in an eventual 8-point loss to Perdue. Nunn and State Sen. Jason Carter, who lost in his bid to unseat Deal, would be seen as early frontrunners to challenge Isakson.