Coincidences happen. That's where conspiracy theories come from.
Personally, I think it's a consequence of accumulated injuries over years, playing players the last couple of years when not fully fit and an unfortunate (possibly consequential) spate of injuries this year all at the same time.
The signs were there in the Cup final. Players had hauled themselves to the title and were on their last legs physically and emotionally in the final. It seems to me they haven't recovered yet.
Add to that an over-reliance by Guardiola on certain (naturally older) favoured players and a reluctance to try academy players and it's a perfect storm. But like all storms, it will pass.
We will make top four and the CL play-offs, no problem.
Actually, I feel a bit like the players. Absolutely shattered after the last four years of panicking throughout each game about every result. It will be nice to have a year where we can lose a few games and it "doesn't matter". Back to full stress levels next year :)
