Dolphins place rookie Kyle Louis on IR, sign Jaylin Simpson to active roster

Miami's defense is shuffling the back end. The Dolphins placed rookie linebacker-defensive back Kyle Louis on injured reserve and signed cornerback Jaylin Simpson to the active roster off the practice squad.

Louis, a fourth-round pick, exited Sunday's game early and was diagnosed with an MCL sprain expected to cost him a few weeks. The rookie had been ticketed for a meaningful role in the new staff's defense, so the move to IR stings even if the injury itself is not season-threatening.

Simpson steps into the vacancy from the practice squad, giving Miami needed depth in the secondary. With Louis shelved for at least four games, the Dolphins will lean on their remaining young defensive backs while the rookie works his way back from the knee injury.