Arsenal boss Arsene Wenger will discover on Saturday whether Cesc Fabregas will be fit to play a part in Sunday's crunch clash with Chelsea.
Gunners captain Fabregas has been sidelined with a hamstring injury for almost two weeks and has been left out of the Spain squad for the upcoming European Championship qualifiers against Scotland and Lithuania.
Asked about the likelihood of Fabregas returning for this weekend's Barclays Premier League trip to Stamford Bridge, manager Wenger told Arsenal TV Online: "I don't know. It looks a 50-50 but a 50-50 balancing on the negative side. I will find out on Saturday morning."
One headache the Gunners boss could be spared is over the goalkeeping position after revealing Manuel Almunia was even less likely to be fit than Fabregas.
Almunia suffered an elbow injury during last weekend's shock defeat to West Brom, while understudy Lukasz Fabianski shone in Tuesday night's Champions League win at Partizan Belgrade.
Wenger said of Almunia's availability: "That one is even more difficult. He has not been in a regular training session. So I will see."
Abou Diaby will be in the squad but may not start following his ankle problem, but Thomas Vermaelen (Achilles) remains sidelined.
"Vermaelen - no," Wenger said. "Abou Diaby has an 80% chance of being involved. I am not sure if he will be completely 100% but it is 100% he will be in the squad."
Meanwhile, there was positive news about two of Arsenal's long-term injury victims.
Wenger said: "Nicklas Bendtner (groin) should be available after the international break. And Aaron Ramsey (broken leg) is progressing very well."