Arsenal have included Samir Nasri in the squad to face Barcelona at Emirates Stadium on Wednesday.
Nasri suffered a hamstring injury in the FA Cup victory over Huddersfield at the end of January, and it was believed he had little hope of recovering in time for the Champions League second round first leg against Barca.
Having taken part in a training session on Tuesday morning, though, Arsene Wenger has now confirmed he is in contention to feature against the Spanish champions.
"Samir is in the squad and the starting line-up will be decided tomorrow," Wenger told a press conference on Tuesday. "I will take no medical risk. It's good to have him in the squad.
"He's recovered quicker than expected. I said it would be 21 days but it will be only 17 days. Everybody's absolutely adamant that he's completely medically available. It's down to me to make the decision."
Nasri confirmed on his Twitter page: "Hi tweeps good session today im fully fit and back with the squad looking forward to it."
"Rosicky is available as well," he said. "He is in the squad, but there is no Diaby. He has a calf problem that he did against Brazil with the French national team."
Arsenal were dumped out of last season's competition at the quarter-final stage by Barcelona but Wenger is adamant his side has what it takes to get the better of the "best team in the world".
"It's one of the toughest tests," he said. "Barcelona at the moment are the best team in the world. If you knock Barcelona out you have straight away a good chance to win the competition. It is the toughest test in the European Cup, certainly.
"We have a good opportunity to show we are not anymore the team that played against them last year. We have the belief and strong togetherness to show that. I belief in my players, I believe 100% they have the quality to do it."
One player who should be full of confidence heading into Wednesday's clash is Robin van Persie, who has scored ten goals in nine games in 2011.
"I'm very happy because I've always been a fan of Robin," Wenger said. "I bought him at a time when not everyone was convinced, and when he has been fit he has never disappointed me. I've always been very happy that he's here because he's a world class player.
"You exist in our job at the top, top level because you have specific qualities that belong to you. You survive at our level or you make your career at our level because it's you, you have your own qualities and Robin has exceptional qualities."