Last season, Gamarra hadn't played a single minute during the season. The game Juventus-Inter had arrived and we had almost all of our defenders missing due to injuries. Gamarra stepped in as a starter and was secure as hell and we won the game.
Gamarra is the kind of player that doesn't need to have played a lot, before he plays a very important match. His experience is of great value for us, if only the guy was given the chance!
Playing Materazzi as a left back is the most bizarre any manager can do, when he has several other options. If he can play Materazzi-Mihajlovic against Porto, he sure as hell can play it this time too.