A third-round pick, Andrews was among the NFL's elite runners when a shocking knee injury prematurely ended his career. He became just the 318 second running back in NFL history to have two 2,000-yard (combined yards) seasons (the only other player prior to Williams was O.J. Simpson).

When he had his first 2,000-yard year, he joined just four other backs who had done so (Jim Brown, Walter Payton, Wilbert Montgomery and Simpson). In his first five seasons in the NFL (1979–83), Andrews outgained every other back in the entire NFL. The bullish Andrews had 8,382 total yards in those five years (an average of 1,677 per year) to lead all NFL runners.

Andrews set 19 Falcons club records that began in his very first NFL game in 1979 when he ran for 167 yards in a game at New Orleans where he totaled 189 yards. He was selected to the Pro Bowl in 1980, 1981, 1982 and 1983 and made the NFL All-Rookie team in 1979. He retired in 1987.