Former Vice President Joe Biden has selected a running mate and could reveal his decision as early as Tuesday, a source familiar with the matter tells NBC News.

Following weeks of speculation, the upcoming announcement will mark Biden’s most crucial decision to date as the presumptive Democratic nominee.

The VP pick is set to speak at next week’s Democratic National Convention, which begins Monday and runs through Thursday.

News that Biden had made his pick came after NBC News reported earlier Tuesday that Biden’s campaign had assembled a veteran roster of strategists to help navigate the crucible of a fall campaign.

The team includes a pair of trusted Biden veterans who played key roles during his time in the White House and are familiar with the value and potential pitfalls of being a supporting player on the presidential ticket.