Sources say that Vice President Joe Biden will turn down an invitation to participate in the first Democratic debate this month.

Sources close to the VP told CNN that he was not preparing for the Oct. 13 debate in Las Vegas, nor is he expected to participate in it. They also confirmed that Biden is still considering whether or not to jump into the 2016 presidential race, and that his decision will probably not be made until late October.

Earlier this week, CNN released its eligibility criteria for the debate, which gives the vice president leverage to join the debate stage even if he declares his candidacy on the very same day. The rules simply require all of the candidates to have achieved an average of 1 percent in three polls that are recognized by CNN and were released between Aug. 1 and Oct. 10.

National polls show that Biden averages about 5 percent, which is higher than official candidates like former Maryland Gov. Martin O'Malley and former Rhode Island Gov. Lincoln Chafee. As a result, Biden would easily qualify for the debate.

All of the official Democratic contenders -- Chafee, Hillary Clinton, O'Malley, Bernie Sanders and Jim Webb -- are expected to face off in the first DNC-sanctioned debate at the Wynn Las Vegas, reports CNN.

CNN anchor Anderson Cooper has been confirmed as the main moderator of the two-hour primetime debate, while chief political correspondent Dana Bash and CNN en Español anchor Juan Carlos Lopez will ask additional questions. Lead anchor Don Lemon will also participate by reading Facebook questions submitted by Americans.

The debate will air live at 9 p.m. ET on CNN and be hosted by Facebook. Following the CNN debate, there will be at least five other primary debates among the Democratic candidates.