If Walker's USFL and NFL numbers are combined, he ranks as one of the most productive professional football runners in history. Many are reluctant to do this, however, because of the disagreement as to whether the level of play of the USFL was comparable to that of the NFL.
Even without taking his USFL numbers into account, his NFL stats are outstanding. In 12 NFL seasons, Walker gained 8,225 rushing yards, 4,859 receiving yards, and 5,084 kickoff-return yards. This gave him an impressive 18,168 total combined net yards, ranking him high among the NFL's top 20 all-time leaders in that category at the time of his retirement. As of 2007, 10 years after his retirement, he still ranks 8th in all-purpose yardage. He also scored 82 touchdowns (61 rushing and 21 receiving). Walker is the only player to have 10,000+ combined rushing and receiving yards and 5,000+ combined return yards(all of which were on kickoff returns). And also the only player to gain 4,000 yards three different ways: rushing, receiving, and kick off returns. He is one of six players (
Jim Brown, Lenny Moore, Marcus Allen, Marshall Faulk, and
Thurman Thomas) to exceed 60 TDs rushing and 20 TDs receiving. This is all the more impressive considering that he spent his first three years in another league.
Even so, most football experts rank Walker's professional career as something of a disappointment. This must be due to the high, perhaps unrealistic expectations that were placed upon him due to his college career and the scrutiny which was entailed by so much being traded for him by the Vikings. Additionally, he never played on a championship NFL team. Some observers, however, claim that Walker was at least in part a victim of the package of rules changes the NFL had adopted in the spring of 1978, which were widely assumed to discourage offenses from running (rather than passing) most of the time; in addition, the NFL teams on which Walker played seldom used the I-formation, out of which he ran so successfully throughout his career.