Wood let-off a boost for England
There had been fears the 28-year-old could be cited after his shin connected with Welsh fullback Liam Williams' head 14 minutes from time as the back row forward attempted to hack a loose ball towards Wales' line.
Williams was taken from the pitch on a medical cart.
However, the Citing Commissioner Maurizio Vancini decided to issue a warning, a lower sanction.
"Under the Rugby World Cup 2015 Disciplinary Programme, a citing commissioner warning equates to a yellow card in sanction," read a statement from the organisers.
"A combination of three yellow cards or citing commissioner warnings accumulated during the tournament will result in a hearing. Wood is therefore free to play in England's next Pool A match against Australia."
Wood made an apology to Williams on Twitter on Sunday.
"@SanjayWills really relieved to hear ur back on ur feet ok mate. Horrible to see u stretchered off because of me. Hope u hav a speedy recovery," he said.
Williams, though, could pay a heavier price for the clash as he can only make a gradual return to play under head injury protocols.
These could see him ruled out of Wales' remaining pool matches against Fiji and Australia.
For injury-hit Wales that would be yet another blow to their back division.
Wales had fullback Leigh Halfpenny and scrumhalf Rhys Webb ruled out before the World Cup started, while centre Cory Allen (hamstring) was sidelined after their opening 54-9 win over Uruguay.
Star centre Jonathan Davies was ruled out earlier this year after suffering a serious injury playing for his French club Clermont.
And as well as losing Liam Williams, Wales also saw wing Hallam Amos (shoulder) and centre Scott Williams (knee) go off injured against England.
Agence France-Presse
