Scott Quinnell is troulbled by the same knee that he hurt last summer in Australia and will miss Saturday's match against Scotland at the Millennium Stadium.
"It is the same knee, but it is a new injury," said Quinnell. "I just need a few weeks rest before the Heineken Cup semi-final for Llanelli against Leicester."
However, there was good news for Wales as Llanelli fly half Stephen Jones came through his club's Principality Cup quarter-final and also Cardiff centre Jamie Robinson was back in action in another quarter-final.
Both Robinson and his brother Nicky, along with Mark Taylor (Swansea) and Ian Gough (Newport) were in training with Wales over the weekend and Nathan Budgett (Bridgend) is hoping to be fit after limping off against LLanelli at half-time last Saturday.
Quinnell was the only one of the 22 players of the squad beaten by England at Twickenham who did not train.
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.