That's the strong likelihood, which was expressed by the statement the Indianapolis Colts put out Monday. As most of the nation took the day off for Labor Day, the Colts said Manning will likely take the rest of the week off. That means Manning's streak of never missing a start since being taken No. 1 overall in 1998 is on life support.
In a league that depends on the kind of offensive grace that Manning provides, this is a huge problem. Manning is the face of the NFL and his style of play drives people to games, either through buying tickets or watching from the comforts of their couch. Over the years, team after team around the NFL has thrown the ball with increasing regularity as Manning carried the torch that was passed to him from Dan Marino.
"During the last week, the rate of improvement in Peyton's rehabilitation process slowed," the Colts announced. "Over the weekend Peyton experienced soreness in his back. It was originally thought to be a normal reaction to his rehabilitation regimen. When the soreness persisted, the Colts medical team decided to initiate diagnostic tests and to consult with a number of specialists around the country who have been involved in Peyton's case from the outset. That process continues.
"As a result of the most recent development the doctors have decided that Peyton will not practice. His participation therefore, in Sunday's game versus Houston will likely be doubtful. We will update his playing status as required by NFL policy as the week goes on."
[Related: Colts delay Jim Tressel's employment]
Worse, Colts owner Jim Irsay has sent a series of cryptic tweets this past week that make it sound like Manning's season is in jeopardy. As noted by Nate Dunlevy, who follows the Colts under the blog 18to88.com, Irsay has written the following messages since Friday:
• "Weather forecast ever changing … ominous storm clouds gathering … it never rains under my umbrella."
• "There was the Rams-K Warner Sup year./There was Patriot 2001-Brady Sup.year.--- Every year. is interesting n unpredictable in NFL!!!!"
• "This ain't a dream no more … it's the real thing … give me a second, let me get it 2gether, just got 2 pick myself up off the floor."
• "Got 2 code the darkness … prepare u 4 an alternative journey."
• "No quarter? NONE ASKED! We made a promise, we swore we'd always remember, no retreat, no surrender; like soldiers in a winter's nite, a vow 2 defend."
• "Stampedblue and Jon Bauges/random or silly tweets, they r not … ur not hearing what I'm saying … riddle n codes r done 4 a reason, but it's there."
• "It's BETWEEN the lines, you will find … what you can only find here."
Anyone who has spoken to Irsay more than a few times knows that he can push the eccentric line. His combination of text-speak and penchant for quoting song lyrics (even passing music fans recognize the line from Bruce Springsteen's "No Surrender") can be confusing, but these hints look obvious. Irsay, who just gave Manning a five-year, $90 million contract, appears to be signaling that Manning could be out for awhile.
What does all of that have to do with the lockout? Manning had neck surgery on May 23 in Chicago. It was the second time in 15 months he had surgery to deal with a pinched nerve problem. At the time, Manning and Irsay both downplayed the recovery time.
As the lockout progressed over the next two months, Manning didn't have access to the Colts training staff, a group he has worked with his entire career. He wasn't allowed to under the rules of the lockout. The people who knew Manning's body best weren't allowed to see him.
It's impossible to know if his recovery would have been better if he'd been around the Colts' staff. It's a good bet it couldn't have been worse.
What's sad about this is how much it means for not just the Colts, but the entire NFL, to lose Manning, even for a short time. Manning is one of the most important players in the history of the game and he's still in his prime. He struggled at times last season, but mostly because of injuries to players around him, such as tight end Dallas Clark(notes) and wide receiver Austin Collie(notes).
Anyone who enjoys the modern game knows that Manning is a symbol of it. He isn't merely the most valuable player the Colts have, he is the standard bearer for quarterback play. You want to know why Tom Brady(notes) and the Patriots throw so much now? It's partly because they lost to the Colts in the 2007 AFC title game and coach Bill Belichick recognized he had to change.
Want to know why so many teams with good quarterbacks now challenge the Pittsburgh Steelers with three- and four-receiver attacks? It's because of the success Manning started to have against them after years spent figuring out Pittsburgh's version of the 3-4.
Sadly, Manning's streak will come to an end. Even if he can make it back soon, it's going to take him awhile to be sharp. If he's out for an extended period, the Colts are toast in the AFC South.
Just another reason to hate the lockout.
Other popular stories on Yahoo! Sports:
• Tiki Barber remains unemployed and sad
• College football's Week 1 surprises/disappointments
• Video: Which NFL coaches are on the hot seat?