Scarlets flanker Aaron Shingler and Dragons wing Ashton Hewitt have been ruled out of Wales' summer tour.
Shingler, 30, suffered a knee injury in the first half of Scarlets' Pro14 final defeat against Leinster at Dublin's Aviva Stadium.
Shingler will be replaced by Cardiff Blues' Josh Turnbull.
A replacement is yet to be named for uncapped Hewitt, who suffered a shoulder injury in training on Thursday.
On Sunday Wales travel to Washington to play South Africa on 2 June before two tests against Argentina.
Hewitt had been called up alongside fellow Dragons player Aaron Wainwright and Ospreys prop Rhodri Jones for English-based trio Luke Charteris, Josh Adams and Tomas Francis who were released from the squad.
Adams, Charteris and Francis were withdrawn from the trip after being named in Warren Gatland's initial squad because they were unavailable for the South Africa game which falls outside of World Rugby's official international window.
Shingler's absence is another back-row injury blow for Wales after Cardiff Blues flanker Josh Navidi was ruled out of the tour earlier in May because of a shoulder problem suffered in the Challenge Cup final victory against Gloucester.
Shingler's Scarlets team-mate, Scott Williams, could also be a doubt for the tour with a shoulder injury.
"Scott is in the changing room now and we will have to chat with him," coach Wayne Pivac said after the Pro14 final.
"I can't give you an update at the moment."
Forwards: Rob Evans (Scarlets) (25 Caps), Wyn Jones (Scarlets) (8 Caps), Nicky Smith (Ospreys) (18 Caps), Elliot Dee (Dragons) (7 Caps), Ryan Elias (Scarlets) (2 Caps), Rhodri Jones (Ospreys) (16 Caps), Samson Lee (Scarlets) (38 Caps), Dillon Lewis (Cardiff Blues) (2 Caps), Adam Beard (Ospreys) (2 Caps), Bradley Davies (Ospreys) (62 Caps), Seb Davies (Cardiff Blues) (4 Caps), Aaron Wainwright (Dragons) (*uncapped), Cory Hill (Dragons) (15 Caps) (Co-Captain), James Davies (Scarlets) (1 Cap), Ellis Jenkins (Cardiff Blues) (6 Caps) (Co-Captain), Ross Moriarty (Gloucester) (20 Caps), Josh Turnbull (Cardiff Blues) (8 Caps).
Backs: Aled Davies (Scarlets) (8 Caps), Gareth Davies (Scarlets) (32 Caps), Tomos Williams (Cardiff Blues) (*uncapped), Gareth Anscombe (Cardiff Blues) (15 Caps), Rhys Patchell (Scarlets) (8 Caps), Hadleigh Parkes (Scarlets) (6 Caps), Owen Watkin (Ospreys) (4 Caps), Scott Williams (Scarlets) (55 Caps), Hallam Amos (Dragons) (15 Caps), Steff Evans (Scarlets) (9 Caps), George North (Ospreys) (73 Caps), Tom Prydie (Scarlets) (5 Caps)
2018 summer tour schedule
Saturday, 2 June
South Africa v Wales (Robert F. Kennedy Memorial Stadium, Washington, USA)
Saturday, 9 June
Argentina v Wales (San Juan del Bicentenario Stadium, San Juan)
Saturday, 16 June
Argentina v Wales (Estadio Brigadier López, Santa Fe)