the biggest problems with Ponson was he didnt take part in the inbetween game conditioning (and I kid you not, running) and his attitude on the team. From what I hear he was a nice guy, but took his job for granted, and players noticed that he did not participate in the off day conditioning. It might have rubbed guys the wrong was and set a poor example. On top of all that he never pitched into the 7th, and was constantly taxing the bullpen.
Perhaps if he stayed in shape, he could have gone longer and kept his job. He wastn THAT bad of a 5th starter when he wasnt gassed.