Priestland aggravated his Achilles tendon in the warm-up of the Scarlets’ RaboDirect PRO12 semi-final on Friday evening and will miss the two-test tour.
Patchell, 19, who has scored 147 points in 22 appearances for the Blues this season and Haverfordwest born Parry, joined up with the training squad when they met for the first time this morning.
Ken Owens, Scott Williams and Liam Williams who picked up knocks in the defeat to Ulster, will continue to be monitored by the National Squad medical team.
