Alstott still needs 83 yards to get to 5,000. Considering that he only had 80 rushing yards last year and that his coach is an "Aryan" disciple of the Caste System, there's no guarantee he'll reach what is now a modest milestone.
In the days of Jim Taylor 5,000 yards was significant, but the increase of the schedule from 12 to 16 games, the elimination of the running role of the fullback in favor of all the running done by a single halfback, and a fixation with getting "X" amount of yards by backs and receivers as status symbols in the "new" black NFL, made the old ways of achieving statistics in the game passe.
If used as a featured tailback, Alstott would have gained well over 10,000 yards and could easily have led the league in rushing yardage on at least one occasion with his bruising style that would have regularly worn down defenses in the second half of games. Instead he was used as a change of pace back with Warrick Dunn, which greatly negated the effect of regularly making use of his bull-like strength combined with decent speed, elusiveness and moves.