All of those are fair questions, but the matter everyone should be concerned with is whether Manning is the same Hall of Fame-caliber quarterback that lit up scoreboards before the neck injury kept him sidelined all last season.
His final performance of the preseason against the San Francisco 49ers, one of the NFL's best defenses, gives reason to believe Manning is the same guy. The 15th-year quarterback looked like he hadn't missed a beat, completing 10-of-12 passes for 122 yards and two touchdowns—all in the first quarter.
Manning's impressive showing was enough to catch the eye of Pittsburgh Steelers defensive coordinator Dick LeBeau. Known as arguably the best defensive mind in football, LeBeau told Sports Illustrated's Peter King he thought Manning looked like his old self this preseason.
"I don't see much difference in him, quite honestly," LeBeau said. "He did everything he needed to do to show he still can play the position at a high level."
On Sunday, LeBeau will turn 75 years old, but admits that facing Manning was not something on his birthday list.
"That's not a real appetizing part of this birthday, trying to defend one of the greatest quarterbacks of all time," LeBeau said in King's article.
However, Manning is facing a tough task as well, going against a stingy Steelers defense. LeBeau's unit was the No. 1 overall defense in 2011, while also sporting the NFL's best pass defense (172 yards allowed per game).
The Steelers will be without safety Ryan Clark, though, due to a sickle-cell trait. Clark was forced to sit out the loss at Denver in the Wild Card Round of the playoffs last season. His absence is a major loss in the secondary, which was exemplified by Tim Tebow's 316 yards (most by any Steelers opponent in 2011-12), two touchdowns and a 125.6 QB rating in the Broncos' 29-23 overtime victory.
If Tebow, known for his passing deficiencies, can put up those numbers, Manning will surely have a huge game on Sunday night. His 6-1 career record against LeBeau's defenses is more reason to believe in No. 18.
After a full offseason with targets Eric Decker, Demaryius Thomas and familiar faces Brandon Stokley and Jacob Tamme, Manning should have enough comfort in the offense to perform at a high level this season.
Doubters will say that Manning's best days are behind him, but with more than 54,000 career passing yards and 399 touchdown passes (both the most of any active quarterback), doubt this living legend at your own risk.