Arsenal boss Arsene Wenger admits Santi Cazorla's injury woes are a blow.
Wenger has revealed the club will hold a mini investigation into Cazorla's injury saga.
The Spaniard has played since October 19 after aggravating and ankle injury in the Champions League clash against Ludogorets.
Wenger said: "I don't have any regrets but we will have a debrief about the situation.
"For me it is a bit difficult to see step by step exactly all along.
"We have these problems inside clubs - if a player is Spanish, he wants to go to Spain. If he is French, he wants to go to France, if he is English he wants to go to England. There is always that little conflict between the medical care of what you have in the club, and the freedom of everyone to be treated where he wants to be treated.
"We always try to find a good compromise, with good communication with people in their local country and usually it works very well. It is normal that you want to see a specialist in your own country, because that is where you have been educated.
"For me it's very bad news (the injury). You always know the date of the surgery but never the date where the player will play again."