CONCORD, N.C. -- Being on the bubble is not where you want to be -- in sports or in any other profession. It usually means step up the performance significantly, or in some cases do something miraculous to impress management, or you're out.
It's a step above "You're fired!"
Some athletes spend their entire careers on the bubble, always having to prove something to work beyond their current contract. Some are on the bubble because they're at the end of their careers and have to prove they can beat Father Time one more season.
Some are on the bubble because they never fulfilled the high expectations that were thrust upon them.
Every year, somebody is on the bubble in NASCAR. Jeff Burton was on it at Richard Childress Racing in 2006, having gone four seasons without a win. He responded with a victory and 20 top-10s to finish seventh in points and has been off the bubble ever since.
Kyle Petty was on the bubble at Petty Enterprises last season. OK, he's been on the bubble for a lot of years but was protected because his father owned the company.
But after he went winless for a 13th straight season and the team merged with Gillett Evernham Motorsports, Petty is out of a ride.
At least a dozen drivers could be on the bubble for this season, but since the people who write the story budget at ESPN.com wanted only five, here you go:
He put himself on this list.
"My goal is to go win some races this year, run up front so that I don't have to say this is my last year," Waltrip said recently. "But if I don't do those things, if I can't compete at the level that [David] Reutimann does or NAPA expects, then I probably won't get to do this again in 2010."
Most team owners don't put themselves on the bubble. That Waltrip did proves he (a) is smarter than some credit him with being, (b) realizes that maybe there was something to Clint Bowyer's comment that Waltrip was "the worst driver in NASCAR -- period" or (c) all of the above.
Were he not the owner, Waltrip probably would have been off the bubble and on the unemployment line a few years ago. He hasn't won a race since 2003 at Talladega Superspeedway and has only one top-5 and four top-10s in the past three seasons combined.
In 725 Cup starts, Waltrip has only four wins, a winning percentage of .006. And although that might be a good number when you're taking a sobriety test, it's not good enough to keep a job.
The good news? Waltrip apparently realizes this.
The 2000 Cup champion says he's as excited as he's been in his career. He should be. He has shed that anchor called the No. 43 at Petty Enterprises for the No. 96 at Yates Racing.
Assuming he is given competitive equipment -- and he should be, thanks to Yates' alliance with Roush Fenway Racing -- the onus is on 44-year-old Labonte to show the past five seasons have been a fluke.
In case you haven't heard, Labonte hasn't won since the 2003 season, when he was at Joe Gibbs Racing. He has only 12 top-5s since then, none in the past two seasons.
Top-10s haven't been too plentiful, either. He has had 31 over the past five years and only five in the past two. David Gilliland, the driver he knocked out of a job, had four.
As nice as Labonte is, as admirable as it was for him to stick with the Pettys for as long as he did, his numbers have to improve dramatically for him to stay behind the wheel.
"I look at this as a reset," Labonte said. "I figure the next race I win will feel like the first one because you have success and you want more success, if you really want to do it. It's about winning and being the best you can be in the sport that you're in."
It's also about being on the bubble when you don't win.
How many times has McMurray been touted as the next breakthrough driver? He was proclaimed as that in 2004 at Chip Ganassi Racing after finishing 13th in points the previous season. He finished 11th.
He was again in 2005. He finished 12th.
He was again in 2006, his first season at Roush Fenway Racing. He finished a very disappointing 25th.
He's back in that high-hopes position again this season after completing 2008 with five top-10s over the final six races, including three straight thirds, to wrap up the year 16th in the standings.
But how many times can you be dubbed the breakthrough driver before somebody says you are what you are? McMurray hopes he is good enough to make the Chase. He hopes to crack the barrier that has stood between being a contender and pretender.
If not, he'll still have a job. He's too young and has shown too much promise to be cast aside.
But another year like the past six and he's definitely a candidate to lose his spot at Roush Fenway, which must contract from five teams to four in 2010. He wouldn't go far -- only to Yates Racing, which partners with Roush.
He might wind up there anyway.
But if McMurray is to break out of the mold of a Chase bubble driver, this might be his last chance.
He has won three titles and the Indianapolis 500 in the IndyCar Series, so nobody questions Hornish's ability to drive an open-wheel vehicle. But one has to wonder how long team owner Roger Penske can afford to continue this experiment with talented stock car drivers waiting in the wings.
In 36 Cup races, 34 last season, Hornish has no wins, no top-5s, no top-10s and no poles. He has led only two laps and failed to qualify for eight events.
On top of that, the ban on testing kept him from getting valuable experience in the offseason.
"I really thought that would benefit me more than anyone else," Hornish said. "Now, with not having the testing, at least I'm with a good team that is not trying to cut back their budget."
That's the problem. He's with a good team, and good teams can't afford to be mediocre -- or worse -- and keep sponsors that will allow them to be good.
Another season like this past one, and Hornish might have to listen the next time the IndyCar Series comes calling.
Surprised to see him here? It's not as if he's going to lose his job if he doesn't win a race, or even fails to make the Chase. As NASCAR's perennial most popular driver, he's still worth more to sponsors -- and team owners -- than anybody else even when he struggles.
Earnhardt made this list not because he's on the bubble of losing his job but because he's on the bubble for winning a championship.
The masses known as Junior Nation expected it to happen last season. Give him Hendrick Motorsports equipment and he will conquer the world, they said.
Well, Earnhardt got the best of everything and still finished 12th, his second straight season out of the top 10 and his third in the past four years.
Judging by the ages of recent champions, 34-year-old Earnhardt doesn't have many years left to be a viable competitor for the title his father won seven times.
He showed promise early in his career, finishing third in points in 2003 and fifth in 2004, when he won a career-high six races. He has won only three times in the past four years, though, turning promise into hope.
And earning a spot on the bubble.
David Newton covers NASCAR for ESPN.com. He can be reached at email@example.com.