Napoli boss Rafa Benitez explained hooking Raul Albiol during victory over Lazio.
The defender was taken off at halftime of the 4-2 win.
Benitez said: "Albiol had a spectacular season. He made one error today and we substituted him because his energy levels were quite low. He seemed sluggish and it might be the start of a virus.
"You can't win with just the attack or just the defence. What you need is a balance between them. We are well aware that we have to improve the way we defend as a whole unit and not just the back four."
