Below, we look at five players who will almost definitely not travel whether due to injury or personal choice.
#1. Sam Simmonds
The England number 8 is a doubt for the rest of the season and could therefore miss the summer, with Simmonds set to meet with consultants over an issue with his hip and groin.
Exeter boss Rob Baxter was cautious in revealing that the back-rower would meet with specialists in the coming days to discuss the best course of treatment.
“We are still monitoring it,” Baxter said. “There are some treatment options, a lot more is going to be known this week. It doesn’t necessarily need to be season over for him but we just need to assess everything correctly.
“Without him getting all the consultants’ feedback, it’s at what level they think any intervention is required at this stage. So I don’t want to say he will definitely be back for England and I don’t want to say he will definitely be back for us at the end of the season because I don’t think it is as simple a prognosis as that.”