My guess is holding out after 1 good season would have a negative impact on his negotiating position going forward (with any team). Unless we're talking about something really ridiculous (not sure what you mean by serious) Taylor will get paid injury or not and will attract way more interest if he plays as well as last year than he would holding out and most likely not playing at all in 2016.
The Bills really can't pay him, any hold out on his part needs to be done with the expectation that he probably won't play or won't be getting his ideal contract. I don't know what negotiations were like between his agent and the Bills but my guess is the Bills tried to make him a reasonable offer and it wasn't attractive enough. What exactly would be Taylor's ideal outcome if he held out?