Mason, 44, met with Vanderbilt officials Thursday and again Friday. He is known in the Pac-12 for excellence in defending spread offenses and also as a good recruiter with a likable personality -- two traits held by former Vanderbilt coach James Franklin, who left to become coach at Penn State.
Mason has been at Stanford for four years, also serving as the Cardinal's defensive backs coach, associate head coach and co-defensive coordinator. He'd be the fifth black coach in SEC history, joining Franklin, Texas A&M's Kevin Sumlin and former coaches Sylvester Croom of Mississippi State and Joker Phillips of Kentucky.
St. Louis Rams offensive coordinator Brian Schottenheimer, Indianapolis Colts offensive coordinator Pep Hamilton and Vanderbilt offensive line coach Herb Hand had also been mentioned as possible candidates for the Commodores' opening, sources told ESPN.
Franklin led Vanderbilt to a 24-15 mark in three seasons and won back-to-back bowl games, a first in program history. He replaced new Houston Texans coach Bill O'Brien at Penn State.
Vanderbilt's last search for a coach was for a program that had played in only four bowls in its history and went 36-114 from 2000 to 2010. The Commodores posted only one winning record (2008) in the 28 seasons before Franklin was hired.
ESPN.com NFL Insider Adam Schefter and The Associated Press contributed to this report.