It happened with me as well. I was 11th in league, out of cup and CL. I decided to tank and I started winning and entered top 7. I got angry and trained all my players at hard again and again at 0% cnd. They got injured. Out of 20, 10 got injured and lost 3 straight matches 3-0 as no complete squad was present. 10th again!!!! YO!!!!!