In fact, a player making a public guarantee is likely to get slapped with a fine and receive a verbal lashing from the head coach.
But when a guarantee is upheld in resounding fashion, it makes for some of the greatest moments professional sports can offer.
On his rise to stardom, Hall of Fame quarterback Joe Namath guaranteed that his New York Jets, who were coming out of the defunct American Football League (AFL), would beat the heavily favored Indianapolis Colts in Super Bowl III. Namath, known more for his long hair and Broadway-ready good looks, was supposed to be no match for the Johnny Unitas, himself a Hall of Famer, lead Colts.
Sure enough, the Jets took an early lead and hung on for dear life as a Unitas rally fell short. Namath ran off the field with his index finger pointed in the air and it was obvious that he had arrived as a venerable superstar.
This is probably the most famous guarantee made in all of sports.
The stage could not have been bigger, the guarantee could not have been bolder and the man issuing the quote could not have been more confident than Namath was on that cold December day.
Ranking up with the Namath in the pantheon of great guarantees is basketball great Michael Jordan made a bold guarantee, no, it was not that he could hit a curveball, in the spring of 1998. After being forced to a seventh game against a talented Pacers team in the Eastern Conference Finals, Jordan held a post game press conference and said calmly, "we will win game seven." Thats all he said and that is all he needed to say.
Game seven at Chicagos home arena, the United Center started predictably, with the Pacers laying the wood to the favored Bulls and Jordans teammates looking around hopelessly for a saving force.
Never one to buckle under pressure, Jordan delivered as he had countless times before a guided the Bulls to a decisive win after being down as many as 16 points in the second quarter. Once again, a heros mettle shined through and the city of Chicago could rejoice one more.
On a smaller scale, a new guarantee broke into American sports lore. Mark down September 14 on your calendar as the day something special happened in the National Football League (NFL).
As the date suggests, there can be no title on the line as no major sport has its championship in the ninth month of the year.
However, the guarantee made as the season entered week two is as uniquely astounding as the Super Bowl boast of nearly 35 years ago.
During the week, Jamal Lewis, a fourth-year running back for the Baltimore Ravens, guaranteed he would break the NFLs single game rushing record in the upcoming games against the Cleveland Browns if he got at least 30 carries. The Ravens responded by handing Lewis the rock exactly that number of times, and Jamal did not disappoint, turning those 30 carries into 295 yards.
To put this record and subsequent guarantee in proper context, a history lesson is in order.
The late Walter Payton, who owns the second spot on the NFLs all-time rushing list, set the single game record for rushing yards when he piled up 275 yards for the Chicago Bears in 1977.
Neither the NFLs all-time leading rusher Emmit Smith nor the elite running backs playing of the 80s and 90s ever threatened the record. Barry Sanders, Terrell Davis and Eric Dickerson all retired without getting close to breaking Sweetness mark.
During another abysmal season for the lowly Cincinnati Bengals, Corey Dillon broke the 23-year-old record by racking up 278 yards against the Denver Broncos in 2000. So it stands to reason that a decade or two would go by without seeing the record seriously threatened again.
It is not totally unfounded that Lewis could have a record setting day, as he has a fairly productive pedigree. As a rookie in 2000, he had over a thousand yards rushing that helped an anemic offense provide just enough support for a dominating defense that carried the Ravens to a Super Bowl win.
However, he tore his ACL during the pre-season and had to miss all of the 2001 season. He never returned to form, and had a mediocre campaign in 2002.
Another piece of evidence suggesting he was not the guy to break the record was that his previous career best was a 187-yard performance, nearly 100 yards shy of the aforementioned record.
So, like Namath, Lewis went against substantial odds to make a prediction about personal production.
Namath led one of the biggest upsets in modern sports history. Lewis pulled off an improbable feat, for which the line in Vegas would have probably been 10,000 to 1.
This is not to suggest Lewis guarantee is better than Namaths.
Clearly Broadway Joe still has the edge 35 years later. However, Lewis proclamation is clearly something special.
He called out a certain opponent on a certain day and said, "I am coming at you, try to stop me." There is no margin of error, you flop and you are likely to wind up on every sports radio shows "jackass of the week" program.
Lewis delivered, however, and brought meaning to an otherwise pointless Sunday in mid-September.
Uncertainty exemplifies why we watch sports. Anything can happen anytime two teams take the field. Best of all, you do not have to wait till the Super Bowl to see someone lay it on the line and give you something truly special.