There's no official word yet on whether Justin Jefferson will return in Week 5. As of the latest wiki update (Oct 2-3), he was ruled out for Week 4 against Miami, and the team is taking a cautious approach — HC Kevin O'Connell said Jefferson "got close" to returning but they won't rush him back. The injury is a low-ankle sprain with no structural damage, which is good news, but the conservative management "suggests Jefferson could miss additional games beyond Week 4 if recovery continues slowly." (from the Justin Jefferson page)
So Week 5 is still up in the air — keep an eye on practice reports later this week. The Vikings also have their bye in Week 6, so the team may choose to give him an extra week of rest to come back closer to 100% for Week 7.