PITTSBURGH (AP) - Three Super Bowl appearances over the past six years, three different starting centers for the Pittsburgh Steelers. Three different right guards, left tackles and right tackles, too.
In fact, along the Pittsburgh's offensive line, only left guard has had a modicum of stability over the course of Super Bowl wins following the 2005 and 2008 seasons and even through last season's Super Bowl loss to the Green Bay Packers.
In a league _ and on a team _ in which stability, chemistry and cohesiveness are valued in constructing an elite offensive line, the Steelers have managed to consistently remain among the NFL's best despite constant change.
This preseason, the reigning AFC champions have auditioned no fewer than four candidates for the job of starting right guard, and virtually every prominent player on the unit has missed practice time due to injury and/or contract issues.
The depth has been questioned enough that the team brought back six-year veteran Trai Essex less than a month after coaches had determined he was too out of shape to re-sign as a free agent.
Yet somehow, the Steelers aren't all that concerned. After all, they've overcome it before.
"I think every guy in here knows that when your number's called, you've got to answer the bell, and we've been successful with that for the most part," right tackle Willie Colon said. "But having that solid (starting) five out there is going to be really important for us starting the season."
Colon missed all of last season with an Achilles injury and sat out the first week of this training camp because of the post-lockout rules governing free agents.
But Colon and Pro Bowl center Maurkice Pouncey _ himself briefly bothered by a pesky ankle this camp _ are the most steady components of the line. Chris Kemoeatu is entering his fifth season as the starting left guard. But he opened camp on the physically unable to perform list due to left knee swelling.
"As of right now, we've got a bunch of new guys stepping into the (first-team) scene," Kemoeatu said, "and I'm still trying to get back to 100 percent. But we've got two weeks left.
"It's all about repetition and trying our best to build up the communication with everyone. It doesn't really matter who you play next to here because every one of them are capable guys who have been around who can step in there."
Pittsburgh cut former starting left tackle Max Starks this summer and re-signed the player who started the final 12 games of last season (including playoffs) in his place, Jonathan Scott.
Like Colon, Scott was forced to sit out the first week of camp. Then, he left Thursday's preseason game vs. Philadelphia due to a minor knee injury _ the same fate that fell his backup, second-round pick Marcus Gilbert.
That compelled the Steelers to move Tony Hills back to left tackle after Hills had been given the start at right guard. Ramon Foster, Doug Legursky and Chris Scott also are in the running to be the starter at right guard for the season opener Sept. 11 at Baltimore.
"We've shown from the years past, with the never-ending revolving door with us, that we've really just got to focus on the next person in line who's going to step up so that there weren't be any dropoff in play or capability," said Legursky, who started the Super Bowl at center in place of an injured Pouncey. "No matter who's in there on gameday, that's who's going to lead us into battle.
"We've preached from Day 1 that, especially on the offensive line, position flexibility is probably most valuable thing you have. And that's why we'll go get somebody like Trai."
Essex has started 25 games over his six seasons with Pittsburgh _ some each at tackle and guard. He also can play some center, but he did lose his job as the starting right guard early last season.
His contract expired, Essex said Steelers coaches weren't shy in letting him know when they saw him at quarterback Ben Roethlisberger's wedding last month that Essex was too overweight for them to re-sign him.
"They see the huge difference between then and now," Essex said this week after he agreed a one-year contract on Monday. "They know I spent some time losing weight. They'd been keeping in contact with me, but this would have never happened if I didn't take the time to lose weight in the first place."
Essex married this year, and his lockout was spent "living it up" between bachelor parties and honeymoons.
Word from Steelers coaches hit home, however.
"It made me realize that if I want to stay in this game and if I want to play, that I have to really change some habits," Essex said. "I made some bad habits, and the lockout was bad for me. But also, this was blessing."
Having the Steelers temporarily turn their back on him was one thing. The phone not ringing from any other club was another.
But it says just as much about Pittsburgh's depth on the line as it does about Essex's successful diet that he was lining up as the No. 2 left tackle in practice the day he returned to the team.
That sounds alarming _ and it probably would be, for most teams. Somehow, though, the Steelers find a way to make it work year after year.
"It starts, first, with our coaches in the room," Foster said. "Coach (Sean) Kugler and coach (Harold Goodwin), they do a good job of making sure everyone knows everything. They treat everyone as if you're going to go in to play the game each week.
"We don't mind who's beside us playing. We just keep it rolling with whoever's in there."
The Steelers play host to the Atlanta Falcons on Saturday.