You gussed it. Georgia native, Auburn graduate, and 3rd round pick William Andrews is the greatest Falcon to don #31, and it isn't really close.
Andrews cracks the Falcons records book with 5968 yards on the ground, four consecutive Pro Bowl appearances from 1908-83, and two-time 2nd team All-Pro honors in 81' and 82'. Known for his sheer power, catching ability, and heavy contribution to the 80s Falcons, Andrews is a shining light in a sometimes dark Atlanta past.
Watch out, Ronnie. Ouch.
Unfortunately, what could have been a Hall of Fame caliber career was cut short after William suffered ligament damage to his knee during a 1984 preseason game that sidelined him for two seasons.