Arsene Wenger believes it is possible for Tomas Rosicky to return to action before Christmas although the Arsenal midfielder is still troubled by his niggling hamstring injury.
The 27-year-old Czech Republic international has already spent more than eight months on the sidelines since limping out of last term's 3-0 victory against Newcastle United at the Emirates Stadium.
Wenger told the Gunners' official website: "I monitor Rosicky's progress very closely, but at the moment it is very difficult to put a date on his comeback.
"We are not pessimistic about the future of his career, but we still need more patience.
"If he comes back before Christmas we have done very well - but I think we can achieve that, so in December he can play again."
Meanwhile, Wenger is determined to build on the Champions League success against FC Porto and bounce back from the shock Premier League defeat to Hull City when the Gunners face Sunderland on Wearside this weekend.
"When you go to Sunderland, you want your team to be completely at its best, and focused. I believe what happened last week will help us to do that," he added.
"The pain was big but the response was good. I believe we have a healthy attitude in the squad and that has been shown against Porto.
"We want to show we have learned from the defeat against Hull."