- Players involved in the Ireland Rugby World Cup programme
- Players that have signed from other clubs/provinces (with the exception of overseas players)
- Under-20 players not involved in the IRB Junior World Championship
- Selected other players
A small number of players, whom the Ulster management consider to be in need of extra recovery time, will return a week later on Monday, June 27.
Johann Muller and Pedrie Wannenburg will return on July 4 as they have been playing rugby for the past 18 months solid - they took part in the Super 14 season in South Africa before joining Ulster and have played almost every game throughout the course of the season over here too.
Ulster has nine representatives in the Ireland Under-20 squad participating in the IRB Junior World Championship in Italy next month. They will get time off after that tournament and will rejoin the squad on July 18.
Ruan Pienaar will go to South Africa after the Barbarians game this weekend and probably will not return until after the Rugby World Cup in October. Simon Danielli is likely to have a similar involvement with Scotland.
Ulster's strength and conditioning coach Jonny Davis said that while players need some complete rest, they are expected to do some conditioning work before they return for pre-season.
"Players do generally need time away from training. The off season is seen as a time when bodies can overcome the physical stress of the training environment," he explained.
"The recovery period is four weeks in duration and gives the players a chance to regenerate their minds and bodies.
"However, for professional players, rest (no training at all) is not the best option when their bodies have been accustomed to activity every day.
"When you withdraw activity from a professional athlete, it interferes with appetite, sleep and mood state. More importantly, it makes the return to training all the harder.
"Active rest and not complete rest is the best option, avoiding structured training sessions and enjoying sporting activity for what it is. It allows the muscles to continue to be worked but away from a competitive environment."
Meanwhile, two of Ulster's new recruits, John Afoa and Jared Payne, are also not expected to arrive in Belfast until later in the year as they still have playing commitments in New Zealand.
Payne will finish the Super Rugby campaign with the Blues and will link up with Ulster sometime in September. At this stage it is expected that Afoa will be named in the All Blacks squad for the Rugby World Cup and will therefore not be available until mid-November.