What happened: Louis had already been expected to miss multiple weeks after an MCL sprain. Miami used the roster opening to bring Simpson up from the practice squad for immediate secondary depth.
Why it matters: The move turns a week-to-week knee issue into a longer enforced absence for a defender expected to handle a meaningful role. It also follows Louis' MCL sprain and forces Miami to reshuffle its defensive rotation early in the regular season.
By the numbers: Injured reserve means a minimum four-game absence, extending Louis' time out beyond the initial few-weeks expectation tied to the knee injury.
What to watch: Watch Miami's next inactive list to see whether Simpson jumps straight into the gameday mix. Louis cannot return until he clears the four-game minimum on injured reserve.