I think Manning and Condon engineered Manning's way out of Indy...and there's a decent chance Irsay was involved. That team was really bad...and Manning wasn't going to spend his last few years on a team with an aging crappy roster with little hope of getting back to the Super Bowl. I think Manning's legacy was incredibly important to him...and he felt he had unfinished business.
Manning's last contract was actually signed in the summer leading up to the 2011 season...less than 7 weeks before he would have the neck fusion. They were in a lockout that offseason...and it wasn't resolved until 7/25...so Manning didn't sign his deal until 7/31.
But at that point, he had had failed TWO surgeries (one in February and one in May I believe)...and still couldn't throw the football 5 yards. There is a fantastic WaPo article out there that chronicles Manning's neck injury and recovery. Manning knew he couldn't throw...and that it wasn't getting better...and because of this and him having access to the best medical care...I think Manning also knew what he would have to do...in regards to the fusion surgery and other treatments (like the stem cell treatment he got in Europe).
But the interesting part is that Irsay, who knew Manning better than just about anybody (and I am sure knew about the surgeries and maybe even Manning's current status), didn't bother to have even a basic physical before making Manning "the highest-paid QB in the NFL"...as he insisted on doing. I know QBs are treated differently...but that what type of business owner makes that type of investment without due diligence (or how does his inner circle of advisors let him). It would have been akin to Ballard giving Luck a big extension in the summer of 2017 when Luck looked like he weighed 170 lbs.
Either Irsay was aware of it all and was involved in Manning's exit...or he took Peyton at his word on his health and was ultimately duped.
But considering they both agreed to include a massive $27M option bonus due the following spring...essentially a poison pill that would end the contract if there even any question about Manning's health...I think it's pretty clear they both knew there was considerable risk due to Manning's neck. But the rub is that it was actually Manning (and Condon) who insisted on the roster option...and I think they did it because they knew what was coming and knew the Colts wouldn't/couldn't pick it up. And they even made the option decision due 5 days BEFORE the start of the league year...so that the Colts would have to pick it up to even trade him.
Basically...Manning would be a FA and would get to choose his next team to cement his legacy...and the Colts would rebuild...which is what Irsay wanted. And most of the fanbase would accept and understand why he left. It was pretty ingenious actually.
That makes sense, but the inconsistencies are what is bad. Denver had no QB's but the game didn't get postponed. When the Titans game was rescheduled, they only had 8 players test positive and 1 was a long snapper and 2 others were practice squad players.