It's not only that, we're playing a much more static game than last season. Pirlo was thriving last season due to our movement, especially when we used the 4-3-3.
Pirlo's game declined similarly at Milan after 2007 when Sleedorf became slow and they did not replace Cafu and Shevchenko, who provided a lot of movement.
Pirlo is at his best when there is a lot of movement. However, he is slower than he was before even although he has never been quick. Looks like age is taking his toll on him.
I'm still very happy to have him but we will have to use him less next season and use Pogba in his place more often.