Defenses will get ranked on the surface by pure yards/game and points/game. But personally I think these are the real defensive stats. And here's how the Rams are through three games:
Yards/play- 8th
3rd down %- 22nd
Red zone scoring (TDs)- 27th
Yards/rush- 4th
Yards/pass- 11th
QB sack %- 27th
Turnovers/game- 15th
Their red zone defense was terrible in week one (4/4 TDs) but has been a big factor in their two wins. Their pass rush is disrupting QBs but just not quite getting home yet (see Aaron Donald). This team needs 2 turnovers/game to boost the offense.