Injuries always play a critical role in pro football, particularly at the end of the schedule, when survival goes hand in hand with success.

As the 2015 season kicks off, several teams didn't survive the preseason too well, and their chances for prosperity have been reduced significantly.

Start with the Panthers, who couldn't have been more eager to see receiver Kelvin Benjamin's progression after a strong first NFL season. Instead, Benjamin tore up his left knee and is gone for the year.

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Carolina lost another wideout, Stephen Hill, to the same injury. Defensive end Frank Alexander has a torn right Achilles tendon. DT Star Lotulelei was bothered by right foot problems throughout the summer.

When Benjamin, who was developing a terrific rapport with quarterback Cam Newton, went down, fellow receiver Ted Ginn Jr. summed up the loss.

''You've got to realize he's our No. 1 guy,'' Ginn said. ''Not having your No. 1 guy on the practice field, it hurts you a little bit. I believe we have the guys behind him to step up and do whatever we need to do to fill the void right now.''

Perhaps. But that's no way to start a season, particularly in a tightly bunched (if mediocre) division.

Also wobbly from knockout punches are the Giants. No one playing safety was safe in the last two months in the Meadowlands.

Since training camp opened at the end of July, rookies Landon Collins (knee), Mykkele Thompson (Achilles tendon), free agent Justin Currie (broken leg), and veterans Bennett Jackson (knee), Nat Berhe (calf), Cooper Taylor (foot), and Josh Gordy (hip) got hurt. Some returned, many did not.

New York never got to see rehabbing receiver Victor Cruz in game action, either. A calf issue sidelined him just when it seemed he would return to the lineup after missing 11 games in 2014 with a shattered knee.

The situation was so tenuous during training camp that Tom Coughlin, hardly an easygoing coach, opted to cut back on some practices.

Some teams are quite capable of overcoming the absences of key players. Green Bay, for one.

The Packers lost brilliant wide receiver Jordy Nelson (knee) for the season, but Aaron Rodgers has a way of making all of his targets better, if not as dynamic as Nelson. Green Bay has the talent throughout the roster to make up somewhat for Nelson being sidelined, particularly if young tight end Richard Rodgers and wideout Davante Adams blossom.

''That's one of the things that I think this system allows us to do is adjust and adapt,'' quarterbacks and receivers coach Alex Van Pelt says. ''I don't think there's anybody better in the league at making adjustments than Aaron.''

Other NFC North teams aren't so fortunate, and not only because they don't have an MVP-quality quarterback. They don't have the depth to handle major injuries.

The last thing the Bears need is a gimpy WR Alshon Jeffery (left calf) now that Brandon Marshall is with the Jets, and top draft choice Kevin White (left shin) is on the physically unable to perform list.

Detroit's best defensive player, linebacker DeAndre Levy, missed the final two preseason games. With Ndamukong Suh in Miami and Nick Fairley in St. Louis, a limited Levy doesn't help the Lions' chances.

Minnesota's questionable offensive line is without tackle Phil Loadholt (left Achilles tendon), meaning rookie T.J. Clemmings must be ready.

''Stuff happens, freak accidents, and it's unfortunate,'' says left guard Brandon Fusco, who played on the right side next to Loadholt the past three seasons. ''He's a hardworking guy and he cares so much about the game of football and he's a big-time locker room guy. It's a big loss.''

And so it went throughout the offseason and preseason. Washington's full-season losses were two of its top three tight ends, Niles Paul (broken ankle) and Logan Paulsen (turf toe), and LB Junior Galette (Achilles tendon).

For St. Louis, it was cornerback E.J. Gaines (foot) who started 15 games as a rookie.

Steelers All-Pro center Maurkice Pouncey (left ankle) is on injured reserve-designated to return. Bills starting CB Leodis McKelvin (right ankle) will miss at least the first six weeks. Bucs RT Demar Dotson (sprained right knee) also was placed on injured reserve/designated for return.

Texans star running back Arian Foster (groin) is out indefinitely. Cardinals guard Mike Iupati (left knee), an expensive free agent addition, will miss time, and starting nose tackle Corey Peters (Achilles tendon) is done.

Another big-money free agent, TE Julius Thomas (hand) is out for September in Jacksonville. The Jaguars' top draft pick, DE Dante Fowler Jr., won't have a rookie season after tearing up his knee. Two other defensive linemen, Sen'Derrick Marks and Andre Branch, are hurt.

Dallas won't have cornerback Orlando Scandrick (right knee). Indianapolis is without DL Art Jones (left ankle) and backup RB Daniel Herron (shoulder) for the season.

The Jets put CB Dee Milliner (right wrist) on IR/return, and lost TE Jace Amaro (left shoulder) and safety Antonio Allen (Achilles tendon) for 2015. QB Geno Smith's broken jaw - from a punch by a teammate who then was cut - should sideline him for a month.

Bengals LB Vontaze Burfict is still recovering from his second surgery on his left knee in January and is out at least six weeks.

OUCH!

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