What happened: Aaron Donald will not play for the Los Angeles Rams in Week 4 against the Philadelphia Eagles because of a back injury. He was unable to participate in any of the Rams' three practice sessions this week.

Why it matters: Los Angeles now has to replace a central piece of its defensive front for a conference game in Philadelphia. The ruling turns a weeklong absence into a firm game-day loss for one of the Rams' most established veterans.

What to watch: The next marker is whether Donald returns to practice when the Rams open Week 5 preparation. Sunday will show how Los Angeles reshapes its interior defense without him.