The issue for the Steelers' defense is uncertainty more than it is unfamiliarity.
Keith Butler has replaced Dick LeBeau as the defensive coordinator, but Butler has been on the staff since 2003 and the anticipation is he'll do little more than tweak the scheme.
"'Coach Butz' is going to keep it the same for the most part," defensive end Cam Heyward suggested after OTA No. 2. "I guess it's just bringing the young guys up and making sure they're up to speed and able to play fast on Sundays.
Even in the event Butler decides to drastically alter the X's & O's, "it's just football," outside linebacker Arthur Moats maintained. "It doesn't matter how you draw it up, it's still going to be the same football.
For the Steelers, it's the collection of guys doing the playing that remains more in transition.
Stephon Tuitt was listed as a starter at defensive end, along with Heyward, and Ryan Shazier as a starter at inside linebacker, along with Lawrence Timmons, on the final depth chart released after the 2014 season.
The door has since been opened for backups Moats at outside linebacker, Cortez Allen at cornerback and Shamarko Thomas at strong safety due to the retirements of outside linebacker Jason Worilds, cornerback Ike Taylor and strong safety Troy Polamalu.
"It definitely has to be the guys who are on the field," Moats continued. "You can have any scheme you want but if you don't have the players that are going to produce and be productive it doesn't really matter.
"The guys that are new to the defense that are going to get more playing time, myself included, we all have to step up and it starts here. You have to make sure we put in the work now, get the details right, so that when the season starts we can hit the ground running."
Moats started 10 games last season, his first with the Steelers, but he has 30 career starts on his NFL resume.
Shazier (five starts) and Tuitt (four) both started fewer than half of the games as rookies in 2014.
Allen has started 18 of 55 career NFL regular-season games, including the first seven in 2014 before he eventually lost his starting job.
The Steelers participate in Day 2 of the 2015 Organized Team Activities at the Steelers practice facility.
Thomas has two starts in 29 career NFL games, both in 2013 and both as an extra defensive back in a sub-package alignment.
And outside linebacker Jarvis Jones has started 11 of 21 career games.
"The biggest thing is the guys, they've been competing every day in practice," Moats said. "Even going back to last year, outside of the guys that were hurt, they were still getting that work every day so we're comfortable with them in this setting.
"When the lights get on it's always a little bit different. As long as we're putting our work in now everything will take care of itself when the season gets here."
Even cornerback William Gay, a veteran of 128 career games and 76 career starts, wasn't inserted into the starting lineup last season until the fourth week.
The defensive players, thus, are trying to become familiar with one another as well as the nuances of Butler's scheme during OTAs.
"You can't build Rome in one day, so that's what we're not trying to do," Gay said. "We're just trying to build, trying to come close together, everybody. I want to re-start and learn the defense again because I wasn't a starter last year (at the outset of the season). I should be making sure I do everything right.
"That's what everybody's mentality is."
Those unfamiliar with Butler's work in the linebacker's meeting room are also trying to come to grips with the way the native of Anniston, Ala. gets his points across.
"His accent's crazy," Moats said. "You get a little subtitle every once in a while, we're good."