Injuries. There are few things that can make the mind of a sport bettor hurt more than trying to figure out how to compensate for them. How much of an impact will the loss of a superstar have on a team? How about the impact of a journeyman player? Have the oddsmakers undercompensated for the injury, or overcompensated? We will explore those questions and more, but first let's look at an example to understand the difficulty of the problem.

There is a school of thought that suggests that the injury of a starting quarterback is worth a three- to four-point adjustment in the point spread. It would be very appealing if it were as easy as that - you could just read about the injury and adjust the spread according to the magic formula. It doesn't take much brainpower to understand just how impossible that is, though. Clearly the replacement of Tom Brady by a guy who hadn't played a game since high school is more significant than the replacement of Tarvaris Jackson by a more experienced, more proven veteran. Does having to replace JaMarcus Russell hurt a team as much as having to replace Peyton Manning would? Of course not.

There are 32 different starting quarterbacks in the NFL at the beginning of the season. That means that there are 32 different, unique situations, and each one needs to be dealt with differently. Trying to equate the impact of an injury to a single number adjustment for is just asking for disaster. Besides, quarterback is just one position, and it doesn't operate in isolation. What happens if the injury of the quarterback comes at the same time as the return of the starting running back? Or if the left tackle were hurt in the same game as the quarterback, leaving a backup to protect a backup? Or if the first opponent a backup QB faces is particularly good? Or particularly bad? It can't be simplified.

That's just one position and one sport. The same problems can arise when talking about any of the other positions, and any other sport you can bet on. Wanting to simplify injuries down to a number is understandable, but is foolhardy for most bettors to try to do. There are more reasons for this, too:

Problems with information - Injury reports are notoriously unreliable. Some players are on the list who shouldn't be, some aren't who should be, and some injuries are reported incorrectly. It's tough to make a decision based on the reports because we can't know for sure what the actual status is. Different media outlets can publish different information, and it can be updated at different times. Making important handicapping decisions based on most injury reports would be like picking a winner in a boxing match when you only know one fighter.

We aren't inside the locker room - We like to pretend that we understand the teams that we cheer for, but that's usually far from the truth. We don't really know which players are the most important to a team, and how the team will respond to an injury. Maybe the injured player is crucial, and the teammates will collapse without him. Or maybe they will play extra hard for their fallen comrade. Or maybe they are secretly relieved he is gone.

The stars don't tell the whole story - Most sports fans have a simplified view of how a team works - it's all about the quarterback, or the point guard, or the goalie, or the pitcher. Teams are obviously far more complicated than that. An injury to a star could have a major impact, or no impact at all. Teams are about much more than their stars, so their fate is determined by much more than that star's health.

We aren't in oddsmakers' heads - In order to effectively compensate the point spread for injuries we have to first know how good the original line was. Oddsmakers could have better information than the rest of us, so the line could already compensate for an injury that we didn't yet know about. They could adjust the lines not to compensate for an injury, but for the expected public perception of that injury. Because we can't fully understand what went into a line, and because different factors will be considered in different lines, it doesn't make sense that we would try to use one number to universally adjust for injuries.

So what does it all mean? It doesn't mean that things are hopeless, or that you can't bet on a team as soon as a player is injured. All it means is that understanding injuries and compensating for them in your handicapping is more of an art than a science. You can't solve your problems just by looking for a magic number, but by thinking about the situation, the replacement, the opponent, and other factors that matter you should be able to come up with a sense of the real impact, and whether that impact creates a betting opportunity.