Pressure is a fact of life when you play in the NFL.
The ability to perform under this enormous mental strain separates the All-Pros from the wannabes.
When a team puts a player in a situation where if they falter, the season crumbles, it makes the pressure even more intense.
With that in mind, here's a look at eight players who are facing that kind of stress as training camp begins.
All of them are being counted on to step up and be a catalyst for their team's success.
Seven are on the offensive side of the ball and three of the eight are rookies. Feel free to comment with your own list or differences of opinion.
Jackson is a rookie and the only defensive player on this list.
The Texans were 9-7 last season and are on the verge of becoming a playoff team.
In order to accomplish that they need a solid season from the Alabama product.
Houston lost all-everything corner Dunta Robinson in free agency and Jackson is being asked to come in and be the man.
It might be asking too much for the rookie to replace Robinson, but he'll have to step up and play solidly if the Texans want to go to the postseason.
GM Scott Pioli brought in Cassel from New England and gave him a big contract with the hopes of turning the franchise around.
So far it hasn't happened.
Granted the Chiefs have more problems than you can shake a stick at, but Cassel hasn't helped.
He threw for less then 3,000 yards last season and managed only 16 touchdowns with 16 interceptions in his first season in KC.
Cassel needs to show that his one year of greatness in New England wasn't the result of the system, but his ability to play the position.
If he can't and continues to struggle, it will be a disaster in Kansas City.
With Ben Roethlisberger serving at least a four-game suspension, it's up to Leftwich to keep the ship afloat during the first quarter of the season.
If he doesn't, the Steelers' season could be over before it starts.
Leftwich is a solid, not spectacular quarterback, who can get the job done.
He has some weapons in Rashard Mendenhall, Heath Miller, Hines Ward, and Mike Wallace, so he isn't being left on an island.
The big question mark is a weak offensive line that got weaker when Willie Colon was lost for the season.
Can they protect him?
If not, Leftwich will have to have his head on a swivel.
And the coaching staff will cross their fingers and hope he can do the job.
Bradford not only has a franchise, but a whole city, on his back.
The Rams are 6-42 in the last three seasons and make no mistake; they won't have a winning season this year either.
But Bradford could put them on the right track and give this beleaguered franchise and their fanbase some hope.
It might be asking too much for a rookie with little talent around him, the exception being Steven Jackson, to come out and be like Peyton Manning.
But if he can rack up at least four or five wins the future will look a little brighter.
On the other hand, if he stinks up the joint or gets pounded into submission, the damage done to him, physically and mentally, could be too much for Bradford to rebound from.
Mathews has the unfortunate task of replacing future Hall-of-Famer LaDainian Tomlinson in San Diego.
Tomlinson holds all the Chargers rushing records so the pressure will be on Mathews right from the start of training camp.
The Chargers are once again the favorites in the AFC West and the expectations and pressure on Mathews are very high.
One good thing in his favor is that Norv Turner loves to run the football, so he'll get plenty of chances to prove himself in 2010.
Dallas let veteran Flozell Adams go in the offseason, and will go with Doug Free at the all-important left tackle spot.
The Cowboys are taking a risk on having an unknown commodity like Free protect Tony Romo's blindside.
Adams is 35 and starting to wear down, but even at his advanced football age, he is one of the best left tackles in the NFC.
The organization and the fans believe a Super Bowl is possible in 2010. How far they go may come down to how will Free plays.
If the gamble pays off, Jerry Jones and Wade Phillips will look like geniuses. If it doesn't, the Cowboys will once again sing those dreaded playoff blues.
If anyone needs to have a breakout season it's Matt Leinart.
The former USC star has yet to live up to the hype as a first-round pick in 2006.
Leinart has a chance to inherit (he must beat out Derek Anderson) a team coming off back-to-back playoff berths, including a Super Bowl appearance. He also spent four years learning from Kurt Warner and that can only help his cause.
The bad news is that he's inconsistent, doesn't have much pop in his arm, and that the Cardinals lost a boatload of talent in the offseason.
A lot is expected of Leinart this season. He was supposed to be Arizona's starter four years ago.
Now he gets his chance in a make-or-break year.
Talk about pressure.
No one, and I mean no one, understands it more than Kevin Kolb.
Kolb replaces Donovan McNabb, a man who owns almost every career passing mark in franchise history, as the starter and must maintain the success the Eagles have had during the previous decade.
The Philadelphia fans demand excellence and if Kolb falters or shows any signs of weakness, it will be like a feeding frenzy of sharks with Kolb as the chum.
Don't forget the presence of McNabb down in Washington and what kind of pressure will build if the Redskins rise and the Eagles drop.
Andy Reid feels that Kolb has the skill set to succeed and lead the team back to the playoffs.
If he doesn't, it will be a long, cold winter in Philadelphia.