Major injuries that changed the trajectory of the NFL season

The saying goes that the NFL is a game of attrition, and there's a lot of truth to that. Look at the teams that survive through the playoffs and it's generally ones that have had a good deal of luck when it comes to keep their best players healthy.

This year is no different. Teams can have seasons derailed, or greatly altered by key injuries. Sometimes they're lucky and there is the proverbial next man up who performs just as well, if not better. More often than not, however, it can be a setback a team never recovers from. These are some of the biggest injuries of the 2016 NFL season.

Minnesota Vikings - In many ways, even despite their recent three-game slide, it's remarkable that Minnesota has played as well as they have. They lost presumptive starting quarterback Teddy Bridgewater for the season in the preseason, then star running back Adrian Peterson for significant time just a few short weeks into the year. The Vikes' problems with blocking are owed in large part to the injuries to tackles Matt Kalil and Andre Smith.

Pittsburgh Steelers - Like Minnesota, Pittsburgh is experiencing a rough patch as midseason arrives. The Steelers have lost three in a row, and though Ben Roethlisberger only missed one full game in that stretch, he was limited in large parts of the other two losses. Pittsburgh's defense is far from living up to its reputation, and it doesn't help that key starters like Ryan Shazier and Cam Heyward have missed significant time.

Dallas Cowboys - Tony Romo's preseason injury might have been a blessing in disguise for the team, depending on how you feel about him. There's no disputing that Dak Prescott has played incredibly well as Dallas has gotten off to a 7-1 start. Prescott has only had a few even middling games, which has kept the Romo comeback talk mostly at bay, though you have to imagine it's bound to return if at any point the rookie struggles this season.

Miami Dolphins - Jay Ajayi has come out of seemingly nowhere to become a star, rushing for more than 200 yards in back-to-back games, then going over 100 yards again in Week 9. While Ajayi was the presumptive starter throughout most of the offseason, it was veteran Arian Foster who supplanted him as the regular season began. Foster went down with an injury a few weeks into the season. That coupled with Ajayi's ascendance spurred Foster to announce his retirement midseason.

Houston Texans - Houston remains atop the AFC South, though how much of that is merely the lack of decent competition in the division is probably considerable. Brock Osweiler has been a big disappointment, putting more pressure on a defense that is without J.J. Watt for the remainder of the year. The Texans are still able to win, though they've only once held a team under 20 points since Watt was hurt, after doing it twice the first two weeks of the season.

Buffalo Bills - While the team jettisoned offensive coordinator Greg Roman early in the season, with good immediate consequences, the defense hasn't exactly been dominating either. It doesn't help that Marcell Dareus has only appeared in one game this season, either due to suspension of injury. Dareus seemed to be on the verge of being a breakout star in 2014, though dropped back to Earth some the following season and now can't get back on the field.

Seattle Seahawks - Kam Chancellor returned to practice this week, and the Seattle defense is going to need all the help it can get going against the Patriots in Week 10. Chancellor has only played in four games in 2016. The Legion of Boom has remained strong in his absence, though as we saw early in 2015, it can make a big difference having him in the lineup.

San Diego Chargers - San Diego is just starting to play well though you'd have to wonder if their offense wouldn't be even better if they hadn't lost both no. 1 receiver Keenan Allen, as well as Danny Woodhead early in the season. Allen only played eight games in 2015, yet was on pace for a 1,400-yard season. If he could avoid injury, he would be a significant part of the Chargers offense all the time.