The Brazilian striker came off against Manchester United in their FA Cup third round loss.
Asked if the injury may be long-term, Arteta stated: “Big worry, that’s my feeling. He had to come off on a stretcher with a lot of pain, touching his knee. It’s not looking good.”
He added on whether it was the same knee as before: “No, I think it's the other one. The worrying factor is the feeling that he had. When he had to come off and the pain that he was in.”
Asked about fan pressure to sign an out-and-out striker, he finished: “No, but I mean we miss from various ways, from different players. I understand guys that but I cannot love my players more and my focus, I’m very much focused on the ones that we have to perform at the highest level, that’s it, the rest is not in our hands, my hands.”