PITTSBURGH — The coach is edgy and unhappy. The quarterback is dealing with another concussion, his fourth since 2006. The defense isn’t the same with two of its best players injured and out. Every kickoff is creating anxiety. Every game is becoming an adventure.

Has it really been only

10 months since the Pittsburgh Steelers won the Super Bowl?

The Steelers won’t say so, but they expected to be cruising toward the playoffs by now, with all but two starters back from an experienced, proven team that won its second Super Bowl in four seasons. Their schedule is much softer than last season’s, with no Colts, Patriots, Cowboys, Giants or Eagles to be found and a healthy mix of Lions, Browns and Raiders.

Instead, they’re 6-4 and locked in an unanticipated struggle merely to make the playoffs. Injuries, special teams breakdowns, the surprising Bengals and a post-Super Bowl letdown appear to be conspiring to torment a team that looked to be championship-ready only a few weeks ago.

The Steelers still can salvage a season in which they’ve lost two in a row, including an inexplicable 27-24 overtime loss in Kansas City on Sunday. But they’re running out of time

– and, with key starters such as Troy Polamalu, Aaron Smith and Chris Kemoeatu injured and out, they’re running out of players.

“If we address our ills and really don’t blink in the face of adversity and let that guide our energy and decision making, continue to do the things well that we’re doing well, we should be fine and should be able to correct those issues,” coach Mike Tomlin said Tuesday. “In the short term? Uncomfortable? Absolutely.”

Edgy, too, a word Tomlin used several times during a news conference that lasted nearly twice as long as usual.

And for good reason.

The Steelers have won 10 games or more six times since 2001, so they’re hardly ready to give up on their season. AFC North leader Cincinnati (7-3) showed its vulnerability by losing at Oakland, and only one of Pittsburgh’s remaining opponents has a winning record.

However, the Steelers are going into Sunday’s game at Baltimore (5-5) with yet another big worry, franchise quarterback Ben Roethlisberger’s latest concussion.

He has been their best player all season, and they shudder to think what might happen if he goes down, especially with backup Charlie Batch out with a broken left wrist.

Four years ago, the Steelers were 7-5 and looked to be in worse shape than they are now, yet they rallied to win eight consecutive games and the Super Bowl. But while that team was confident and combative, this one appears confused and uncertain.

The four kickoff return touchdowns they’ve allowed in five games are undermining everyone’s confidence. The coaches wonder why the special teams players lack the pride and commitment to not allow such breakdowns; the players wonder why the coaches can’t correct it.

There’s also starting to be finger-pointing, something the Steelers almost never do – and, as right tackle Willie Colon said, something they can’t do.

Players on both sides of the ball are unhappy with some playcalling, especially a third-down toss sweep by backup running back Mewelde Moore that lost 3 yards and ended the Steelers’ only overtime possession in Kansas City.

“I’d do it again,” Tomlin said.

He might be the only person in Pittsburgh who would.

Some players want to run the ball more; some want to blitz more. Other players are raising questions about team unity.

Tomlin personally accepted the blame for the Chiefs loss, saying it’s on him to have his team better prepared.

“The difference between winning and losing is so little you’ve got to be on top of your game (every week),” running back Rashard Mendenhall said.

While the Steelers are No. 1 defensively, just as they were the last two seasons, they’re clearly not the same without Polamalu, one of the NFL’s best players.

He’s missed five full games and all but a few plays of a sixth with two left knee injuries, and the Steelers lost four of them.

He isn’t expected to play in Baltimore.

The Steelers also gave up some of their renowned toughness when Smith went down with a season-ending rotator cuff injury in mid-October.

The secondary, especially without Polamalu, is ordinary, allowing seven pass plays of 30 yards or more.

Linebacker LaMarr Woodley isn’t making the game-changing plays he often made last season, and nose tackle Casey Hampton isn’t the shutdown run-stopper he’s often been.

The Steelers also have forced only

14 turnovers, fewer than half as many as league leader New Orleans (29).

Offensively, the Steelers keep shifting away from the build-around-the-run philosophy that has been the franchise’s foundation since the 1960s.

That’s requiring Roethlisberger to shoulder an increasing amount of the workload, and Mendenhall often seems to be overlooked at key moments despite being on pace for an 1,100-yard season.

Super Bowl MVP Santonio Holmes, blanketed in almost every game, has made only one touchdown catch and none in nine games.

Still, Tomlin said, “We’re capable of moving the ball on anyone.”

Tomlin is referring to the Ravens’ game as Redemption Sunday – though the Steelers will need more than one good week to redeem this season.

“We’re preparing with an edge because we’d better,” Tomlin said. “The situation dictates it.”

So does the calendar.