If he needs surgery then he will be out of the Wales reckoning for this month and looking at only playing again next season.
Jones is named in the U21 squad to face Estonia on May 10th (Tallin) and 24th (Wrexham) in crucial qualifying games, and inbetween there is a friendly in Port Talbot against Cyprus which will keep the squad together.
The games against Estonia are qualifying matches with the winner over two legs taking part in next season U21 Championship. For the losers it's a whole year without competetive football.
It's also likely he could be called into the senior squad as well. But all that depends on the knee.
Two other Dragons are in the U21 squad. They are defenders Mke Williams and Simon Spender.
U21 squad
Hennessey (Wolves), Price (Ipswich), Bale (Southampton), Duffy (Portsmouth), Spender (Wrexham), Morgan, Nyatanga (Derby), Wiggins (Crystal Palace), Williams (Wrexham), Crofts (Gillingham), A Davies (Yeovil), Jones (Wrexham), Tudur-Jones (Swansea), Ledley (Cardiff), Calliste (Liverpool), Cotterill (Bristol City), C Davies (Verona), McDonald (Cardiff).