A striker lives off his confidence. Lewandowski has currently none. He never found his form after his early season injury. I hope he turns it around, for his and our sake.
His first two seasons, he started excellent and disappeared in the second half of the season. Now he's bad in the first half, so let's hope he'll turn up later in the season.
Part of his current form has obviously to do with age, but part of it due to no confidence due lack of form. Most of his decision making and movement became lately too slow, because he overthinks many situations and plays less with his instinct. It should be the other way around. If you become slower physically, you need to get faster in the head to balance it out.