Swansea half-back Gavin Henson, Bath scrum-half Andy Williams and Newport pair Andy Powell and Hal Luscombe have all ruled themselves out of the Under 21 World Cup which commences for Wales against Italy in Johannesburg's Ellis Park next Thursday.
The prodigious Henson was expected to be named as part of coach Chris Davey's 26-strong squad but the 20 year-old has surprisingly ruled himself out - handing the Wales number 10 jersey to rival Nicky Robinson.
Davey confirmed, "Gavin has made himself unavailable for the World Cup, we are not really sure why.
"He has not had the best of seasons although he started the Six Nations Championship in good form for us, I only hope that the added competition for places at Swansea next season will bring out the best in him."
The Welsh World Cup campaign has also been denied the services of up-and-coming Newport no 8 Andy Powell who feels he needs to rest after a demanding season.
Bath scrum-half Andy Williams and Newport centre Hal Luscombre have also declined the offer of a place.
However Davey is confident the side can live up to expectations.
"Having been seeded fourth we have to target a top four finish," he added.
"The boys have tried and tested themselves at Six Nations level and proved they can compete very well. This will be another step up from that and will be a very good experience. The opening game against Italy should be a good one to get us going."
After the Italian game, Wales take on Argentina on Tuesday June 18 with their final game against favourites New Zealand on Friday June 21.
The team will be skippered by Swansea's Matthew Bayley.
Wales Under 21 World Cup squad:
G Swayles (Swansea), M Nuttall (Pontypridd), K Morris (Caerphilly), L Roberts (Cardiff), N Jones (UWIC), M Jones (Neath), M Bayley (capt, Swansea), S Williams (Newport), N Robinson (Cardiff), M Hook (Newport), M Phillips (Llanelli), C Miller (Cardiff); P James, A Jones, P Matthews (all Neath), C Jones (Llanelli), M Miles (Northampton), G Morris (Pontypridd), B Griffiths (Llanelli), L Tait (Cardiff), L Charteris (Newport), R Jones (Bridgend), R Williams (Ebbw Vale), G Williams (Llanelli), R Sowden-Taylor (Cardiff), R Jones (Newport)
Nearly 40 players were involved in the first Wales Under 18 training session of the season. WRU National Performance Manager Gethin Watts is excited at the potential shown by the group and expects the Regional Under 18 Championship to hone their skills even further.