He was our best midfielder in the CL final season. Just remember how we all went berserk once they reported that he got a bad injury with the NT just before the CL quarters that year. In Vidal's and Pirlo's worst seasons with Juve, he was the main guy.
Something similar happened at the start of last season. He played only 1 and a half matches during that disastrous start we had until late October and we got fixed once he came back.
We can't rely on him so much.