Kentucky Secretary of State Alison Lundergan Grimes (D) will announce Monday whether she'll run for Senate in 2014 against Senate Minority Leader Mitch McConnellAddison (Mitch) Mitchell McConnellSenate passes 0B defense bill Overnight Health Care: New GOP ObamaCare repeal bill gains momentum Overnight Finance: CBO to release limited analysis of ObamaCare repeal bill | DOJ investigates Equifax stock sales | House weighs tougher rules for banks dealing with North Korea 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.

Grimes will make a statement to reporters at 3 p.m. after meeting with supporters.

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 YarmuthKentucky Dem jabs at Mnuchin over eclipse comments Democrats see ObamaCare leverage in spending fights CBO survives two House amendments targeting funding 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.