Bob was recently tested by a WWE doctor, who is friends with The Undertaker, and he was alarmed when he was bleeding all over him in the Hell In A Cell. Bob then got another test was was told he was fine, which is what he initially thought as he has had tons of blood baths, always drank, and never made anyone else sick before. He is blaming the doctor for alarming everyone about it when there was really nothing to worry about.
Taker was alerted and was furious at Johnny “Ace” Laurinaitis, who knew the results of the test and didn’t tell Taker. Johnny Ace had to go to a house show and personally talk things out with a very unhappy Undertaker.
As you’ve probably guessed, these events are likely what lead to his release from the company.