Complex sentence: Davis also recorded 21 rushing touchdowns, making him the only 2,000 yard rusher to record 20 or more touchdowns in a season, and he had reached the 1,000 yard mark only only seven games into the season.
Split into simpler sentences: Davis also recorded 21 rushing touchdowns in his 2,000 yard season, the only 2,000 yard rusher to do so. Davis had reached the 1,000 yard mark only only seven games into the season.