Look at Davids, we signed him as a legend and with the greatest of respect to him he was bloody awful, he kicked lumps out of people yes but it was like playing with 10 men most time i saw him play
How was Davids awful? he was great in his first season for us and added steel to our midfield which desperately needed it.
Pirlo is still a wonderful player, he probably wants a new challenge as he's spent his career in Italy.