Chicago Winds Media Guide (1975): Mark goes into his 2nd pro season with potential to become one of the finest running backs ever to play professional football. A collegiate supestar, the 6' 220 pound Kellar led the nation in rushing yardage with 1,719 yards on 291 carries during his senior year at Northern Illinois. That year he scored 16 touchdowns and averaged 156.3 yards rushing per game. Career-wise, he ranks among college football's all time top ten rushers, having collected 3,745 yards.

A top draft choice (6th) of both Chicago of the WFL and Minnesota of the NFL, Mark decided to stay in the Windy City and display his talents before the home town fans. Mark exploded into stardom as a rookie scoring 15 touchdowns, five of which came against the Hawaiians in the fourth game of the seasaon. Of his 15 scores, 9 came on the ground and 6 through the air. At the time Mark broke his foot against Southern California on September 11, he was leading the WFL in scoring with 108 points and in rushing with 778 yards on 119 carries. Although he only played in 11 of his team's 20 scheduled games, Mark was the team leader in total points when the season had ended. A fine receiver, Kellar also managed to pull in 28 passes for 342 yards and a 12.2 average.