Johnny Manziel recently stated on Shannon Sharpe's podcast that the Browns QB room was not a home for him. The implication was that Hoyer was not a supportive teammate.
Let me state first, football is a painful game and many athletes resort to the use of medication, at all levels of football. I have empathy for all those athletes, including Johnny Manziel. The use of medication to manage pain often devolves into addiction.
Surely the story of Johnny Manziel is not quite that simple, but only those who know him might understand the battles he has faced.
That said, it is a well known fact that Manziel during his first season with the Browns dedicated literally zero effort to improve his game and often showed up late and hung over for practice. Frankly, I would expect Brian Hoyer to lose patience with any teammate who gave less than his best, not to mention a teammate that admits to never watching film.