The injury-plagued Frenchman has not featured for the Gunners at all this season after tearing the anterior cruciate ligament in his left knee in March 2013.
Speaking after watching his side move back into the Premier League's top four with a 3-1 victory over West Ham United at the Emirates Stadium on Tuesday, Wenger revealed that Diaby is now fit enough to rejoin his colleagues on the practice pitch after 13 months on the sidelines.
However, he stressed that the 27-year-old would need some game time in non-competitive matches before he would contemplate throwing him into Arsenal's pursuit of Champions League qualification.
"Diaby is back in full training on Thursday. It's very difficult to say because he's not played for over a year now," he told reporters.
"It's difficult for me but he looks physically fine but he has to play one or two games before I can consider bringing him back."
Diaby, who signed for Arsenal in 2006, has not managed a 20-game top-flight season since 2009-10.