Concussions have become a hotly debated topic in the last several years, specifically when it comes to the NFL and its management of the players in the past. It has led to rule changes that have tried to protect players both on and off the field, to documentaries (League of Denial) and in a forgotten way, the loss of a player's job.

With the way the San Francisco 49ers and Kansas City Chiefs have played this year, November 11, 2012 is a fairly significant date. The path both franchises have taken since then has been a lost storyline with both teams emerging as Super Bowl contenders this season. Unfortunately, during the ninth game of 2012 for the 49ers, a concussion changed the careers of two quarterbacks, and two franchises as well. 

With 1:10 left in the first quarter, starting quarterback Alex Smith suffered a concussion as he slid to avoid a hit from St. Louis Ram linebacker Jo-Lonn Dunbar. However, Smith turned his back late and was hit by Dunbar around the neck area. Smith would remain down for a brief moment as he held his facemask on the ground. He did stay in the game to throw a touchdown pass to Michael Crabtree in the second quarter. Smith was then taken out of the game and the rest, as they say, is history. While Smith sat on the bench, the Colin Kaepernick Era was born.

It is always a shame to see a player lose his job to injury, especially a concussion, but for the Chiefs, the 49ers, Smith and Kaepernick, it changed everything. I want to make it clear that I think concussions are an unfortunate reality of the game and that players are risking their future well being when they take the field every Sunday. We have seen some players leave the game in a good place, and we have seen others, ufortunately, take their own lives as a result of the head trauma incurred on NFL Sundays.

Thankfully, in this situation, all four parties involved have had a happy ending. Kaepernick ended up taking over as quarterback for the 49ers. While Smith and the 49ers were successful, Kaepernick seemed to propel the offense to a whole new level. He had a livelier arm, an ability to hurt teams in the run game and push the 49ers a different level.

The result of the switch to Kaepernick? He led the 49ers to a 5-2 record for the rest of the 2012 season which included wins over the Chicago Bears and New England Patriots. It also saw the 49ers finish with a No. 2 seed in the NFC Playoffs. With every bullet pass and long stride he took on galloping runs to the endzone, his legend and allure only grew.

His sterling play only grew throughout the playoffs and he almost led the 49ers to a last-minute gam winning drive in the Super Bowl. They were five yards away from that elusive Super Bowl title.

Along the way, he made "Kaepernicking" a fad with his kissing-the-forearm celebration. He even made himself one of the best young quarterbacks in the league and helped usher in the hot new NFL scheme with the execution of the read option.

After coming off a stellar 2011 season, where he threw for 3,177 yards, 17 touchdowns and five interceptions while leading the 49ers to a 13-3 record Smith was benched for the rest of the season. This benching came despite leading the team to a 6-2-1 record to start the 2012 season.

After throwing for 1,737 yards, 13 touchdowns and five interceptions before the concussion, he never touched the field again for the rest of the 2012 season. He sat quietly on the bench as the purple and gold confetti came down from the Mercedes-Benz Superdome rafters.

As the offseason began, rumblings began as to what would happen with the two quarterbacks. Fortunately for the Chiefs, they were able to take advantage of the 49ers "problem" and acquired Smith for a third round pick. (The pick is now a second-rounder as the Chiefs will finish better than 8-8 on the season)

Now, the Chiefs are 9-0 as they head into the bye week and have matched their best start in franchise history, which was set in 2003. While Smith hasn't played lights out this season, he has managed the game well enough for their dominant defense to win them games. This season, Smith has thrown for 1,919 yards, nine touchdowns and four interceptions.  

The move to Smith also gave the Chiefs stability at the quarterback position for the first time in a long time. Before that, the Chiefs suffered with the likes of Matt Cassel and Brady Quinn under center. The move allowed the Chiefs to improve elsewhere. Instead of having to gamble in the draft for a quarterback, they improved the offensive line with the No. 1 overall pick OT Eric Fisher. They also re-signed wide receiver Dwayne Bowe, signed cornerbacks Sean Smith and Dunta Robinson and signed wide receiver Donnie Avery.

Meanwhile, the 49ers have continued asserting themselves as one of the NFC's elite teams this season while also doubling as a Super Bowl contender. Kaepernick has continud to show why he is one of the best young quarterbacks in the league. Except for games against Seattle and Indianapolis, Kaepernick has been a steady hand in both the passing and running game. On the season, his statistics aren't fantastic either, having thrown for 1,584 yards, nine touchdowns and five interceptions and rushing for 294 yards and three touchdowns. However, he has yet to play a full season in the regular season (15 combined starts between 2012 and 2013) and the sky is the limit for the future. Despite playing without talented wide receiver Michael Crabtree, he has helped the 49ers to a 6-2 record thus far. 

While concussions should not be taken lightly at all and should not be celebrated, this specific instance has worked out well for all parties involved and changed the direction of two franchises. Who knows, maybe both teams will meet in this year's Super Bowl.