Jimenez suffered a fractured skull in horror collision

The 29-year-old Mexican international received treatment for 10 minutes on the pitch before being taken to hospital.

Wolves -- who won the game 2-1 for their first win at Arsenal in 40 years -- said he would remain under observation for a few days.

"Raul is comfortable following an operation last night, which he underwent in a London hospital," read the club statement.

"He has since seen his partner Daniela and is now resting. He will remain under observation for a few days while he begins his recovery.

"The club would like to thank the medical staff at Arsenal, the NHS paramedics, hospital staff and surgeons who, through their skill and early response, were of such help.

"The club ask that Raul and his family are now afforded a period of space and privacy, before any further updates are provided in due course."

Luiz stayed on the pitch with blood seeping into a white bandage wrapped around his head until half-time.

Arsenal manager Mikel Arteta defended the decision to keep the Brazilian on saying he had shown no signs of concussion and was only withdrawn as the Brazilian was concerned about the cut.

However, there have been renewed calls for temporary substitutes to be used as they are in rugby union whilst the player is given a thorough examination.

"Too often in football we see players returning to the pitch having undergone a concussion assessment only to be withdrawn a few minutes later when it is clear that they are not fit to continue," said Luke Griggs, chief executive of brain injury charity Headway.

"That is the very reason why we urgently need temporary concussion substitutes in football.

"You simply cannot take a risk with head injuries."

Football's lawmakers IFAB have opened the door for concussion substitutes to be used on a trial basis with the English Football Association hoping to do so in this season's FA Cup.