There are many factors to include when looking at the most valuable players in the National Football League. For example, just because Adrian Peterson might be one of the best all-around players in the NFL, it doesn’t make him one of the most valuable. In order for that to be the case, a player must play on a contending team. At least, that’s one of the factors I take into account. 

Another factor is who said player might have behind him on the depth chart. Let’s look at San Francisco 49ers quarterback Colin Kaepernick as a case study. Is he one of the top-five signal callers in the NFL? Obviously not at this point in his career. But with Blaine Gabbert behind him on the 49ers depth chart, Kaepernick immediately becomes a valuable player. The same can be said for numerous individuals who wouldn’t necessarily warrant MVP consideration at first glance.

Today’s article is going to check in on eight players, who if injured, would spell doom for their respective teams. Once again, these aren’t necessarily the best players in the NFL. Instead, the factors we’ve decided to use indicates their overall importance for the contending team. On that note, you will not find players in this article who are on teams that mainstream experts don’t consider serious playoff contenders in 2014.

1. Peyton Manning, Quarterback, Denver Broncos

Courtesy of Fox Sports: Manning has won five MVP's for a reason.
Courtesy of Fox Sports: Manning has won five MVP’s for a reason.

This one goes without saying. While Brock Osweiler looks to be much improved from previous seasons, you simply don’t replace one of the best quarterbacks in NFL history with a guy that hasn’t started a professional game and expect the same results. Denver has done a tremendous job building an elite team around Manning, but his importance to the team goes much further than pure talent. Manning is essentially an offensive coordinator on the field and one of the most intelligent signal callers to ever set foot on the football field.

Manning accounted for 74 percent of the Broncos yards and 78 percent of their offensive touchdowns last season. That’s obviously one of the reasons he earned a fifth NFL MVP award. If Manning does go down to injury, Denver drops from serious Super Bowl contender to mid-tier wildcard team.

2. Andrew Luck, Quarterback, Indianapolis Colts 

Courtesy of Fox Sports: Luck is currently the model of what teams look for in a young QB.
Courtesy of Fox Sports: Luck is currently the model of what teams look for in a young QB.

Even more so than the man he replaced in Indianapolis, Luck represents the most valuable player to his specific team than any other player in the NFL. By now you already know the story. The former No. 1 overall pick took over a Colts team that won two games the previous season and helped them to a surprising 11-5 record in 2012. He followed that up with a division title last season, while accumulating 77 percent of the Colts total offense and 71 percent of their total touchdowns.

If Luck were to go down to injury, the task of leading the Colts to a second consecutive AFC South championship would be left to an over-the-hill Matt Hasselbeck. The former Super Bowl quarterback is about eight seasons removed from being an above-average starting quarterback in the NFL. Outside of Luck, the Colts aren’t much more than a five-win football team. That much is certain right now.

3. Tony Romo, Quarterback, Dallas Cowboys

Courtesy of Huffington Post: As crazy as it sounds, Romo is one of the most valuable players in the NFL.
Courtesy of Huffington Post: As crazy as it sounds, Romo is one of the most valuable players in the NFL.

One of the most underrated players in the entire National Football League, Romo is pretty much the sole reason that Dallas has contended for a division title over the past three seasons. Without him, Jason Garrett and Co. are nothing more than bottom feeders in the NFC. He’s averaging 4,300 yards and 30 touchdown passes since the start of 2011. During that span, Romo has accounted for three quarters of the Cowboys entire offense as well as 77 percent of their offensive touchdowns.

Unfortunately for the Cowboys, the 34-year-old quarterback is returning from offseason back surgery and is just getting back to playing shape. If Romo were to go down with injury, Dallas’ starting job would fall into the hands of former Cleveland Browns first-round pick Brandon Weeden. We can already draw a conclusion about how that would turn out. In reality, the Cowboys are a last-place team without Romo on the field.

4. Earl Thomas, Safety, Seattle Seahawks

Courtesy of USA Today: Along with J.J. Watt, Thomas stands above the rest of NFL defenders.
Courtesy of USA Today: Along with J.J. Watt, Thomas stands above the rest of NFL defenders.

The only defensive player in this article, Thomas is simply one of the most valuable players in the entire league. In fact, an argument could have been made that he deserved MVP consideration last season. Quarterbacks completed just 19-of-29 pases when targeting Thomas last year. More than that, he possesses the most range of any safety in the modern era. And that’s saying something considering some of the center fielders that have taken the field since the AFL/NFL merger some 45 years ago.

Without sounding like too much of a fan boy, Richard Sherman would be nowhere near the player he is without Thomas on the team. On the other hand. Thomas’ ability translates to all schemes and all defenses throughout the NFL.

5. Colin Kaepernick, Quarterback, San Francisco 49ers

Courtesy of CBS Sports: Losing Kaepernick's dynamic ability would hurt the 49ers big time.
Courtesy of CBS Sports: Losing Kaepernick’s dynamic ability would hurt the 49ers big time.

Some may be surprised to find Kaepernick in this article, but let’s be realistic for a second here. If Kaepernick were to go down with an injury, Blaine Gabbert would mostly likely be under center for the 49ers. As we have seen in extended playing time during Gabbert’s career, this preseason included, he’s nowhere near a starter-caliber quarterback in the NFL. In reality, the 49ers would likely find themselves closer to last place than first if Gabbert had to see extended playing time this year.

As it relates to Kaepernick, his numbers are rather impressive in the grand scheme of things. The fourth-year signal caller has 40 total touchdowns compared to 11 interceptions in 23 career starts. During that very same span, Kaepernick has put up a 93.8 quarterback rating while throwing one interception per 58.1 pass attempts and 63.9 dropbacks. For comparison’s sake, Gabbert has thrown two more interceptions than touchdowns while accumulating one interception per 32.3 pass attempts. In addition to this, the 49ers are averaging over 26 points per game when Kaepernick starts (postseason included). There is no way Gabbert would lead the 49ers to anywhere near that number if he were called on.

6. Calvin Johnson, Wide Receiver, Detroit Lions

Courtesy of ESPN: Johnson is the most valuable NFL receiver since Jerry Rice.
Courtesy of ESPN: Johnson is the most valuable NFL receiver since Jerry Rice.

The Lions are a borderline playoff team with Johnson on the field. Now imagine this team having to take the field without the best NFL wide receiver since Jerry Rice. Honestly, it wouldn’t be a pretty sight. The numbers are absolutely staggering here. Johnson has been targeted by Matthew Stafford 25 percent of the time over the past three season. He has also accounted for 25 percent of Stafford’s completions and 37 percent of the quarterback’s touchdown passes. What is even more amazing than this is the fact that 43 percent of Stafford’s passes that traveled 10-plus yards over the past three seasons were thrown in Johnson’s direction.

Even with the additions of Eric Ebron and Golden Tate this past offseason, the Lions simply don’t have anyone ready to step up if Johnson were to go down with injury. This doesn’t even take into account the fact that Stafford simply isn’t the same quarterback without Megatron on the football field.

7. Cam Newton, Quarterback, Carolina Panthers 

Courtesy of USA Today: Newton's importance to the Panthers cannot be overstated.
Courtesy of USA Today: Newton’s importance to the Panthers cannot be overstated.

It’s hard to imagine a single quarterback in the NFC that has been more important to his team than Newton over the past few seasons. The former No. 1 overall pick has accounted for nearly 300 total yards and 1.92 touchdowns per game during his three-year career. In addition to this, Newton has scored 74 percent of Carolina’s offensive touchdowns since the start of the 2011 season. He’s done all this while throwing just one interception per 35 career pass attempts, which is a stellar number considering what is asked of Newton on a game-by-game basis. The combination of electric play and being able to limit turnovers has helped Newton become one of the best young quarterbacks in the NFL.

While Newton has started every game during his three-year career, he is an injury risk simply because the quarterback has attempted an average of nearly eight rushes per game. If he were to go down with an injury, the Panthers would be bottom feeders in one of the most mediocre divisions of football. This is magnified by the fact that Derek Anderson is No. 1 in line should Newton be sidelined during the season. Just think about that for a second.

8. Jamaal Charles, Running Back, Kansas City Chiefs

Courtesy of USA Today; Charles has taken over for Adrian Peterson as most valuable NFL running back.
Courtesy of USA Today; Charles has taken over for Adrian Peterson as most valuable NFL running back.

It’s rather obvious that Alex Smith needs a good running game and stout defense to be a successful quarterback in the NFL. This is evidenced by the fact that he’s been a winning quarterback in each of the last three seasons with that type of supporting cast. In Kansas City, Charles is the man that makes the entire team go. He accounted for a whopping 43 percent of Kansas City’s total yardage output from the running back position in 2013. Not since O.J. Simpson was dominating for the Buffalo Bills some 40-plus years ago has the NFL seen similar numbers (well maybe Adrian Peterson back in 2012).

Without Charles in the fold, Smith would be the face of the Chiefs offense. This would force him to throw more passes and break away from the game manager title that he has acquired since a breakout 2011 campaign in San Francisco. And that wouldn’t be good for fans at Arrowhead or the success of the Chiefs franchise in 2014.