Injuries are more than the great equalizer in the NFL, they can be the grim reaper for a team’s season. Already, a handful of clubs are dealing with the absence of key players, some of whom are pretty much irreplaceable.

A year ago, two defending division champions, the Packers and Seahawks, were destroyed by injuries. Things aren’t looking up for Seattle in 2009, either, with the litany of lost through two games including all-world tackle Walter Jones; cornerback Marcus Trufant and his replacement Josh Wilson; linebacker Lofa Tatupu; quarterback Matt Hasselbeck; and four-fifths of what was thought to be the starting offensive line when training camp began.

Asked this week if he’s had any similar injury situation in his coaching career, Seahawks head man Jim Mora shook his head.

“No, not in 26 years. Never,” Mora said — ignoring 2008, when he was Seattle’s defensive backs coach and endured the franchise’s worst season in 16 years.

Yet Mora can’t stop to worry.

“Is it overwhelming? Not now, it’s not. It can’t be. You can’t think that way,” he said. “You’ve got to think about one thing and that’s getting ready to win on Sunday. Can’t even think about it. Can’t do it. Don’t have time. Don’t have room in my brain.”

Challenging the Seahawks for the dubious distinction of having the most damaged roster are predicted contenders (Chargers, Eagles) and also-rans (Jaguars, Bills, Buccaneers). The NFL schedule is long enough and difficult enough to navigate with a healthy squad, and an early injury epidemic rarely allows a team to reach its potential.

And don’t believe the platitudes coming from coaches’ and players’ mouths. The common response when a starter, particularly a star, goes down, is that his replacement will have to step in and step up.

Players are in the starting lineup for a reason: They are better than their backups. Often, particularly at such critical spots as quarterback and left tackle on offense, nose tackle on defense, there is a hefty drop-off from first-stringer to reserve.

When a team loses such players — as Seattle did last year and is in danger of doing again in ’09 — its chances of staying in the mix for playoff berths and championships plummet. That’s especially true in the salary cap era, when depth at one position is a luxury, and depth at a few is an impossibility.

“It seems like there’s more significant injuries around the league,” said Mora, comparing this season to his tenure leading Atlanta from 2004-06. “I’ve not done a study, nor have I read any study that makes any comparisons, but just off the top of my head, it feels that way to me. We’re talking about guys who are big and fast and strong and powerful and these high-speed collisions. And you know guys are going to get dinged up a little bit.”

The saddest aspect of injuries is how they rob everyone of the chance to watch Troy Polamalu make leaping interceptions and bone-rattling tackles. Or seeing Brian Urlacher play middle linebacker the way Dick Butkus and Mike Singletary once did in Chicago. Or witnessing the development of Colts wide receiver Anthony Gonzalez, who appeared ready for a breakout second season before spraining knee ligaments.

Not to mention having the NFL’s best player, Tom Brady, go down in the first quarter of the 2008 opener with a wrecked knee.

Injuries also can ruin entire units. San Diego’s defense never dominated a year ago with outstanding linebacker Shawne Merriman sidelined, and it probably won’t this season without nose tackle Jamal Williams. We’re seeing just how powerful the Saints can be with the ball now that just about everyone on offense is fit. It’s delightful, but with the track records of Marques Colston, Reggie Bush and Jeremy Shockey, how can we believe some (or all) of them won’t be visiting the infirmary between now and the new year?

Many prognosticators liked the Eagles to not only win the NFC East, but to go to the Super Bowl, a game they fell just short of reaching last season despite some key injuries. That could be way off-base now with quarterback Donovan McNabb (rib), running back Brian Westbrook (ankle), middle linebacker Stewart Bradley (knee, gone for the season), guard Shawn Andrews (back, gone for the season), and tight end Cornelius Graham (knee, gone for the season) missing time.

Carolina was dealt a cruel blow when DT Maake Kemoeatu ruptured his right Achilles’ tendon less than 30 minutes into the first practice of training camp. The Redskins’ already inconsistent offensive line lost right guard Randy Thomas for the season with a triceps injury.

LaDainian Tomlinson is hobbled in San Diego. Same for Brandon Marshall in Denver and Justin Tuck in New York.

Still, nothing compares to Seattle, which has this injury list heading into Sunday’s game with the Bears:

Hasselbeck (broken rib), Tatupu (hamstring), Jones (knee surgery), tackle Sean Locklear (high ankle sprain), center Chris Spencer (torn quadriceps), linebacker Leroy Hill (torn groin), Trufant (disk in back — PUP list), cornerback Wilson (high ankle sprain), receivers Deion Branch (hamstring, following knee surgery), and T.J. Housmandzadeh (back), fullback Justin Griffith (sprained knee), defensive tackle Brandon Mebane (calf), and cornerback Ken Lucas (groin).

Ouch!

Copy the Story Link