Complex sentence: He holds the Cowboys record for a rookie, rushing 1,007 yards in a season and was the only Cowboy to rush for more than a 1,000 yards in his rookie season, until Ezekiel Elliott surpassed 1,000 yards in his 9th game in 2016.
Split into simpler sentences: He holds the Cowboys record for a rookie, rushing 1,007 yards in a season. He was the only Cowboys to rush for more than a 1,000 yards in his rookie season, until Ezekiel Elliott surpassed 1,000 yards in his 9th game in 2016.