When the phrase “for the love of the game” is used to refer to the passion that athletes have for the sports they engage in, the usual images created in one’s mind are those of athletes spending most of their hours each day practicing their craft, often sacrificing life’s simple joys in order to shape themselves into the best sportsmen that they can possibly be. Despite such extreme displays of dedication, “for the love of the game” isn’t usually uttered to refer to athletes who have lost their lives while playing the sports they love. Sadly, meeting death while playing a sport is an unfortunate fate that some sportsmen have had to suffer.

“Just for the love of the game?” might ask those who find the sacrifice of one’s life for sport an unbalanced trade. Well, while most athletes are genuinely passionate about the sports they play, and would probably still dedicate their lives to their sport for nothing more than the pure pleasure of doing so, the reality of professional sports, especially today, is that athletes earn unbelievable amounts of money for their work on the field, ice and track.

Tiger Woods, for example, according to the Forbes 2013 listing of highest-paid athletes, earned a whopping  $78.1 million USD from his salary, prize money, bonuses, appearance fees, and income from licensing and endorsement deals between June 2012 to May 2013. That’s close to $214,000 USD a day.

However, in no way is accounting for the earnings of athletes who have perished in the practice of their professions meant to downplay the purity of their dedication to their sports. It must be recognized that to these sportsmen, the money they earned was a welcome bonus for doing what they loved. Yet, other athletes played at a time when sportsmen didn't make nearly as much as they do today.

Here is a list of 10 athletes who died playing their sport. Their annual earnings are based on their latest reported income and adjusted for inflation:

10. Antonio Puerta (football player) / Annual Earnings: $90,000

The first athlete on our list is a Sevilla FC midfielder who was only 22-years-old when he suffered a cardiac arrest on August 28, 2007 during a home game of the 2007 UEFA Cup. At that time, Antonio Puerta's earning potential was definitely on the rise in terms of both leverage for a profitable new contract and potential endorsement deals for various interested companies. The handsome young footballer had blossomed into a fan-favorite after two particularly impressive performances. First, he scored the game-winner in Sevilla FC’s win over Schalke during the UEFA Cup semifinal of 2006. Then in 2007, Puerta converted a penalty kick to earn the club’s 2007 UEFA Cup championship in a win over Espanyol. Puerta’s official cause of death was listed as “arrhythmogenic right ventricular cardiomyopathy."

9. Chuck Hughes (American football player) / Annual Earnings: $144,000

Chuck Hughes’ stock was definitely on the rise in the NFL during the early 1970s. He had set seven all-time college football records, the most notable one involving 17 interceptions in just one game against Arizona’s college team in 1965. He started out in the NFL playing for the Philadelphia Eagles for three seasons before becoming a Detroit Lion for the remainder of his short career. On October 24, 1971, in the dying minutes of a game versus the Chicago Bears at Tiger Stadium, Hughes suddenly fell forward and lay motionless on the field. Fans thought he had faked an injury for the purpose of stopping the clock. The grim truth, however, was that Hughes had suffered a heart attack that took his life.

8. Duk Koo Kim (professional boxer) / Annual Earnings: $170,000

Deaths resulting from boxing matches are not as unusual as in most other sports, but few of these deaths were of boxers as highly touted as South Korean Duk Koo Kim. His record of 17-1-1 had earned him a handsome fortune and a WBC title bout against the popular Ray Mancini. During the match, which lasted until the 14th of 15 rounds, the Korean looked in a position to win as Mancini was already suffering from a torn ear and a swollen left eye. However, in the end, Mancini won by TKO after flooring Kim with a powerful right hand. Tragically, after the fight the 23-year-old Kim went into a coma and surrendered to brain injuries just four days later. The regrettable outcome caused the WBC to reduce the number of rounds in a bout from 15 to 12.

7. Ray Chapman (baseball player) / Annual Earnings: $175,000

Ray Chapman became part of the Major Leagues in 1912 as the shortstop for the Cleveland Naps. He would enter the baseball record books as the American League leader in walks and runs scored at the time, allowing him to sign one of the most lucrative baseball contracts in the early 1900s. Sadly, in a game against the Yankees on August 17, 1920, pitcher Carl Mays hit Chapman in the head with a spitball that had so much power, fans thought the sound of the ball against Ray’s skull was the crack of the bat hitting the ball. The tragedy started a movement that called for batting helmets to be required for baseball players, and was the reason for the banning of the spitball pitch.

6. Bill Masterton (hockey player) / Annual Earnings: $228,000

In only his first year as part of the National Hockey League in 1968, 29-year-old Bill Masterton was checked by two opposing players, causing his head to slam hard against the ice. Two days later, he died as a result of a brain hemorrhage. The death was especially regrettable since Masterton had shown so much promise with the Minnesota North Stars organization. He scored the first goal for his team that game, helping to justify the handsome sum he had been promised after signing with the club. As a result of the tragedy, helmets in hockey became mandatory in 1979. He has additionally been memorialized through the Bill Masterton Memorial Trophy, often awarded to players who have come back from severe illness or injury.

5. Marc Vivien Foe (football player) / Annual Earnings: $740,000

As an illustration of how lucrative Marc Vivien Foe’s career was, when he moved to West Ham United in January 1999, he was paid £4.2 million, a club record at the time. Unfortunately, during the 2003 FIFA Confederations Cup semifinal, the Cameroonian suddenly collapsed 72 minutes into the game. He would later die at the stadium's medical center, autopsies revealing hypertrophic cardiomyopathy as the cause of death.

4. Reggie Lewis (basketball player) / Annual Earnings: $3.3 Million

It was during training camp in the 1993 offseason that Reggie Lewis, a Boston Celtics player and NBA All-Star, collapsed and lost his life at the young age of 27. There were rumors that cocaine use had contributed to his death, but the official autopsy report showed that Lewis had suffered from a heart defect. The death was a shock to the NBA community that saw so much promise in Lewis whose starting contract was only worth $75,000 USD in the 1987-1988 season, but had ballooned to $3,320,000 USD by 1993.

3. Korey Stringer (American football player) / Annual Earnings: $4 Million

Korey Stringer was a first round draft pick of the Minnesota Vikings in 1995, and he lived up to his billing and sizeable contract. He was an instant standout on offense, earning Pro Bowl honors in 2000. Sadly, that would be Korey’s last season, as on August 1, 2001, he died due to a heat stroke he suffered during training camp. The untimely death prompted the NFL to implement new guidelines for the prevention of heat stroke at training camps.

2. Dale Earnhardt (NASCAR racer) / Annual Earnings: $4.9 Million

Dale Earnhardt Sr. had over 25 years of experience, seven championships in the Winston Cup and a huge collection of prize money from his victories. With such sterling credentials, it shocked the world when the 49-year-old champion driver lost his life at the Daytona 500 in 2001. Earnhardt was defending his lead against his son, Dale Earnhardt Jr., among others, when on the last lap, his car hit a wall. Spectators thought that the crash was a minor one, but just hours later, the hospital Dale was brought to pronounced the decorated driver dead. The tragedy led NASCAR to require head and neck support devices in all cars for racing.

1. Ayrton Senna (F1 racer) / Annual Earnings: $10 Million

A three-time F1 world champion, Ayrton Senna was not only among the sport's most well-loved racers, but was considered by most to be an all-time great. He had built an awesome fortune from his prize money and sponsorship earnings over his ten-year career. Unfortunately, during the San Marino Grand Prix of 1994, while Senna was leading the race on its sixth lap, his car hit a wall after going into a turn at a speed of about 145 mph. Senna was airlifted to a hospital but was later declared dead after suffering numerous injuries from the crash.