Cesc Fabregas is a major doubt for Arsenal's Champions League clash with Celtic after the midfielder was forced out of the 4-1 win over Portsmouth with a hamstring injury.
Fabregas played just 45 minutes of Saturday's victory that was kick-started by two goals from Abou Diaby and wrapped up with second half strikes from William Gallas and Aaron Ramsey.
And Gunners manager Arsene Wenger admitted after the game that his captain had only a slight chance of appearing in this week's European play-off second leg and could be out for up to three weeks.
Arsenal hold a commanding 2-0 lead following the first leg of the tie in Glasgow last week.
Wenger said: "Cesc Fabregas has a hamstring problem. He will be short for Wednesday. Not definitely out.
"If it's a little pull he will be out for three weeks, if it's tightness he could make Wednesday. We will see in the next 48 hours."
Having thrashed Everton 6-1 at Goodison Park last week, Arsenal are already being touted as genuine title contenders.
But Wenger played down his side's chances, insisting it was far too early to start predicting who would be contesting top spot when the season ends in May.
He added: "We have scored ten goals after the first two games but we could have scored more.
"So that's a brilliant start and should create confidence and momentum. The first week was very successful.
"But now we have another week with another test against Celtic and then Manchester United next week.
"But it's too early to talk about the title. I said after ten games in the league you will see a trend.
"It would give me a lot of satisfaction to win the league. But you have to accept the opinion of a lot people in this job and the best you can do is shut up and win your next game."
Diaby's two goals put Arsenal in control of the early stages of the game and Wenger believes the midfielder can have a major impact on the coming campaign.
The player's progress at the club has been hampered by injuries but the manager believes Diaby's time has finally come and even went so far as to draw comparisons with former Arsenal star Patrick Vieira.
"Diaby is a bit more of an offensive player," Wenger said. "But when he decides to play defensively, he is exactly like Vieira.
"When William Gallas decided to move forward, he dropped back and he looked very similar to Patrick when he wins the ball back.
"He is a guy who has quick transition from defence into attack and that is a great quality because no one can keep up with him from box to box.
"It could be his season because he prepared well and he is very sharp and strong. He is all you want to play in the Premier League."
Portsmouth manager Paul Hart felt his side were hard done to when Gallas escaped punishment after appearing to bring down John Utaka when the Pompey winger was clear on goal shortly after Younes Kaboul's header had dragged the visitors back into the game.
"It was a clear foul," said Hart. "I don't like to see people sent off but that was a clear sending off offence. And the Gallas scores the third goal."
Hart's side have lost their opening two games but the manager is hopeful Portsmouth's fortunes are finally turning around and that the long awaited takeover of the club could be completed this week.
He added: "It's gone on far too long. Everyone can see we are a club that needs investment. But we've spent a long time doing nothing.
"We are big boys. You can get on with it or walk away. You have choices in life and I think I work for a good football club.
"The players have been excellent since they came back and we have that good spirit that you could see."