At 36 years old and with four neck surgeries under his belt, people wondered how Manning would respond after taking a big hit.
Would he get right back up? Would he struggle to get up? Would he stay lying on the turf?
Did Peyton still have the arm strength we were all accustomed to seeing?
Although we are only two games in to the 2012 regular season, there's reason to believe that Manning is still an elite quarterback.
He's not back at that "elite" level yet, but in the two games played, Manning has shown positive signs that he is on the road back to being a top-tier quarterback.
Let's take a look at five reasons why Peyton Manning is still an elite quarterback.
Peyton's first test was not simple, as he would face the Pittsburgh Steelers and their physical defense in Week 1.
Against the Steelers, Manning showed that he can still be efficient with the no-huddle offense, his trademark approach in Indianapolis. He showed great decision making and accuracy as he finished the game 19 for 26 (73 percent) with 253 yards.
Manning also added two touchdowns in his return with zero interceptions.
It seemed that after his first game, the four-time MVP looked like the player he did before his injury troubles.
Manning's efficiency with the no-huddle allowed the Broncos to beat the Steelers 31-19 and start the season 1-0.
Essentially, the no-huddle allows Peyton to direct and command this offense like an elite quarterback should.
If Week 2 taught us anything, it showed that comebacks are never easy.
In his second matchup of the season, Manning did not have the same success as he did in Week 1.
In his first Monday Night matchup since November 1, 2010, Manning struggled early on as the Falcons defense showed Peyton defensive schemes he wasn't expecting.
Manning threw three interceptions in the first quarter alone as the Falcons went up 20-0 early on. Manning attempted to keep his team in the game, as he ended the second quarter by throwing his only touchdown of the night to Demaryius Thomas for 17 yards.
In the fourth quarter with the Falcons leading 27-7, Peyton looked like a different quarterback, as he led the Broncos down the field, where Willis McGahee had two short touchdowns.
After seeing multiple Falcons defensive schemes for three quarters, Manning was able to do what he does best. Manning made the correct reads and made the correct adjustments at the line to keep his team in the game.
However, his three early interceptions proved to be too big of a hole for his team to come back, as the Broncos fell to 1-1.
Despite throwing three interceptions in only eight passing attempts against the Falcons, Manning was able to stay poised and lead a furious rally late.
Although he missed a full season last year, Manning used his veteran experience to stay poised throughout the game, despite his early struggles.
Down 27-7 heading into the fourth, Manning never gave up as he kept on looking to attack the Falcons secondary.
Collective, calm and poised, Manning completed 7 of 11 passes for 89 yards in the fourth quarter, as the Broncos were rallying late.
Peyton Manning said in his postgame conference, "I thought we could find a little momentum there, find some rhythm, which we did. We had a chance to win that game. I think we will learn from it and we'll be better for it."
As an elite veteran, Manning knew his team had what it takes to mount a comeback, and he stayed cool and poised as he was only a touchdown shy of tying the game.
The receiving weapons that Manning possesses on this roster are Demaryius Thomas, Eric Decker, Jacob Tamme and Brandon Stokley.
At first glance those names don't seem to be eye-popping, yet Manning finds a way to utilize them in the offense.
Both Tamme and Stokley have played with Manning in Indianapolis, where Tamme showed fine hands and route-running ability while filling in for Dallas Clark.
Last year, Thomas played with Tim Tebow under center, and was able to rack up 204 yards and the game-winning overtime score in a playoff upset over the Steelers. Now with Manning under center, Thomas has already produced for the Broncos offense.
One of the most athletic receivers Manning has played with in his career, Thomas has 13 catches for 188 yards and two scores on 18 targets in only two games. It is clear that he has established himself as Peyton Manning's go-to guy this season.
So as long as Manning is under center, Thomas will be a heavy contributor to this Broncos offense.
Manning will also have Eric Decker contribute, once they get the chemistry going. Decker has fine route-running abilities, something that Manning can utilize. With Decker's ability to run good routes, Manning will trust him in crucial moments and will also target him often.
As an elite quarterback, Manning can utilize all the weapons around him, and get them to contribute to the Broncos offense.
Although his football IQ may be as sharp as ever, his arm power to sling the ball downfield is not the same.
Due to being out of the game for a whole season as well as undergoing neck surgery, Manning can't seem to put as much zip on the ball as he used to. Because of that, Manning must rely on his accuracy and the short to medium passes to keep the offense moving.
As a student of the game, Manning will have to adjust the way he plays due to the lack of arm strength he has shown.
An elite quarterback, Manning is still trying to build off his experiences so far this season to be more efficient and productive in the passing attack.
In Week 1 of the regular season, Manning showed great accuracy, completing 73 percent of his passes on 26 attempts.
In Week 2, he struggled early on but still completed 65 percent of his passes and almost led his team to a comeback victory.
His accuracy is not as sharp as it was pre-injury, but he still has the ability to throw the ball where only his receiver can grab it.