Complex sentence: In 1973, he became the first NFL player to rush for more than 2,000 yards in a season; holding the record for the single season yards-per-game average, which stands at 143.1.
Split into simpler sentences: In 1973, he became the first NFL player to rush for more than 2,000 yards in a season. He holds the record for the single season yards-per-game average, which stands at 143.1.