Arsenal striker Pierre-Emerick Aubameyang has made the bench in the last two matches – the win over Newcastle and Sunday’s defeat to Everton.
Gunners fans questioned Emery’s decision to start Aubameyang on the bench at Goodison Park, with the Gabon international introduced at half-time with his side trailing 1-0.
But Unai Emery explained what was behind his decision.
“He’s getting better and can start,” the Arsenal boss said.
“He had a small problem and he has taken antibiotics for his illness.
“That’s the main reason he didn’t start those two matches.”
Arsenal return to Europa League action as they take on Napoli in the first leg of their quarter-final at the Emirates.
Emery will also make a late decision over the fitness of Granit Xhaka and Laurent Koscielny.