Story highlights Elizabeth Warren and Joe Biden "discussed" the idea of presidential ticket, according to a source familiar with the talks

Sources said the vice president never made a final decision about a running mate and he eventually decided not to run

(CNN) Vice President Joe Biden "discussed" with Elizabeth Warren last year the idea of having her as his running mate for a would-be presidential bid, a source familiar with their conversations told CNN on Thursday.

But that source said nothing was offered and another said Biden never made a final decision.

A source close to Biden said the two met "several times" over the course of the last year and "walked around" the idea of a joint ticket and that Biden wanted to establish a rapport with the Massachusetts senator. He knew that if he were to run for president, "he needed to build his credibility on the left and she knew he would need her blessing," the source said.

The resurgence of the idea for a Biden-Warren ticket comes a pivotal time for Democrats as the presidential primary draws near its end with its front-runner Hillary Clinton, who appears to have a nearly insurmountable delegate lead, heading to the finish line as her opponent, Bernie Sanders, continues to win states.

The source close to Biden also cautioned that the vice president had not yet decided whether he would actually run. Biden ultimately decided against it in October.

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