Earlier on Tuesday, it had been suggested that Arsenal's second-choice stopper would continue to deputise for Cech in Europe, despite only making two appearances since the start of December.
At his pre-match press-conference, Wenger was quizzed about the goalkeeping situation and he insisted that he was happy to reveal his plans.
The Frenchman told reporters: "Nothing to hide. We're here because of the quality of his performances."
In total, Ospina has played eight times this season, with six of those games coming in the Champions League and the other two in the FA Cup.