WASHINGTON (CNN) -- Sen. Joe Biden will announce Thursday the addition of two key presidential advisors who will play an instrumental role in helping the Delaware Democrat amass a campaign war chest.

Kory Mitchell and Byron Kantrow have signed on to Biden's presidential campaign, a Biden advisor tells the Ticker. Mitchell previously served as Sen. Evan Bayh's national finance director, while Kantrow was a New York fundraiser for the Indiana Democrat.

"There is little doubt that Sen. Bayh's finance operation was one of the best in the business," said the advisor, who spoke on the condition of anonymity because the announcement had not yet been made. "It speaks volumes to our campaign that these top aides have signed on to the Biden team."

Bayh himself had seriously considered seeking the Democratic presidential nomination but decided against it, freeing up Mitchell and Kantrow to join another campaign.

"He is lucky to get them, no doubt," said Jeff Forbes, a Democratic operative. "They did a phenomenal job for Bayh."

This weekend, Biden will be the keynote speaker at the American Association for Justice Winter Convention in Miami -- an organization that represents trial lawyers.