While health was always a concern, especially in 2014 when a quad injury severely hampered the Broncos down the stretch, leading to the ouster of head coach John Fox and offensive coordinator Adam Gase, it wasn't until Monday morning that we knew exactly what Manning was dealing with.
Manning is battling a case of plantar fasciitis, a source informed of the injury told NFL Media Insider Ian Rapoport on Monday morning, and has been for more than a week. He experienced discomfort after the turf against the Colts, and had more Sunday. There was some additional pain and inflammation, along with small tearing. It's an aggravation of a previous injury, and the focus now is on getting him healthy.
ESPN first reported the news of Manning's foot injury.
Though fans will likely not stomach this as a reasonable excuse for Manning's performance on Sunday -- he amassed a 0.0 quarterback rating and hurled four awful interceptions, eventually getting replaced by Osweiler -- it does help explain some of the growing pains in Kubiak's offense.
Under center and in the pistol, Manning had more steps added to his drops than ever before. He and Kubiak eventually settled on the pistol as the compromise after a rocky start to the season.
During that time, he was fighting a case of plantar fasciitis.
The recovery timetable here will be interesting. As ESPN noted, Eli Manning played with a fully torn plantar fascia back in 2009, but athletes across all sports suffering the condition have noted the pain and mental anguish often associated with the injury. Sometimes a partial tear is more painful and could require surgery.
Chicago Bulls center Joakim Noah, who labored through a tear during the playoffs back in 2013, said: "It feels like you have needles underneath your feet while you're playing."
Los Angeles Angels slugger Albert Pujols missed a chunk of the 2013 season for a partial tear that required surgery.
In the meantime, the focus shifts to Osweiler, who has the unenviable task of turning this built-to-win ship around. The Broncos, after starting the season 7-0, have lost two straight and still have dates against the surging Bears, Patriots, Steelers and Bengals remaining on their schedule. Osweiler was 14 of 24 for 146 yards in relief on Sunday, with one touchdown and one interception. General manager John Elway, who already dealt for tight end Vernon Davis and was on the verge of closing a deal for Joe Thomas, saw this season as the perfect way to send Manning off -- with a Super Bowl victory. Now? He'll have to wait and see.