Kentucky Secretary of State Alison Lundergan Grimes (D) will announce Monday whether she'll run for Senate in 2014 against Senate Minority Leader Mitch McConnellMitch McConnellDems gain upper hand on budget Overnight Finance: Senate rejects funding bill as shutdown looms | Labor Dept. to probe Wells Fargo | Fed to ease stress test rules for small banks Overnight Energy: Judges scrutinize Obama climate rule MORE (R-Ky.).
The announcement will end months of speculation surrounding the Democrat's intentions for what could become one of the nation's marquee Senate races in 2014 if she decides to run.
Jonathan Hurst, a former adviser to Grimes, said she hadn't yet told him her plans, but that "if she chooses to run, the mechanisms are in place."
Democrats believe McConnell (R ) is one of the most vulnerable Republican incumbents in the nation, citing polling that shows him unpopular in the state.
Grimes, 34, became the favored Democratic candidate to potentially challenge McConnell after actress Ashley Judd announced in March that she would not run.
The daughter of a prominent Kentucky Democratic activist, who has ties to former President Clinton, Lundergan Grimes won the most votes of any Democratic candidate statewide in 2011. Democrats believe has the profile and fundraising ability to take on McConnell in a race that's expected to be fierce.
A recent Democratic poll conducted for Senate Majority PAC showed her tied with McConnell. A separate survey from a GOP pollster gave McConnell a 7-point lead.
She has been under pressure for several months to announce whether she'll run. Rep. John YarmuthJohn YarmuthDem lawmakers: Clinton should have disclosed illness sooner House Dems to GOP on gun reprimands: 'Bring it on' Overnight Regulation: Obama unveils new Arctic drilling rules | GOP pushes regulatory budget MORE (D-Ky.) said last month Lundergan Grimes was doing a "disservice" to the party by putting off a decision.
McConnell aired Web ads last week poking fun at the time Lundergan Grimes was taking making a decision, while a pro-McConnell group launched advertising tying her to President Obama.
If she chooses not to run, however, Democrats' climb to defeating McConnell becomes much steeper.
She has kept her decision-making process low-key, and many of her advisers have gone silent in recent months as she's gauged support for a bid. Hurst said that today's press conference is "not intended to be a big rollout."
"If she chooses to run, we'll do obviously a rollout and a big announcement across the state. If she chooses not to run, she'll explain her decision to supporters," he said.