The Steelers lost center Maurkice Pouncey in August and left offensive tackle Kelvin Beachum in October and still finished No. 3 in the NFL in passing offense and No. 3 in the NFL in total offense last season, so the offensive line must have done something right in 2015.

But guard David DeCastro maintains the line can do even more, and must aspire to do even more in 2016.

"Definitely, no question," he said at veteran mandatory minicamp. "It's one of those things where if you're not trying to get better, you're going to get beat and you're going to get worse.

"So you always have to keep pushing the envelope."

The Steelers pushed back with a next-man-up mentality last season as the injuries struck.

One of the themes throughout OTAs and minicamp has been "welcome back," particularly as it relates to Pouncey.

"He always has that edge, always brings that aggressiveness," DeCastro said. "Regardless of what drill it is, it could be a simple drill, but he's always going full speed."

DeCastro was named a first-team AP All-Pro for the first time in 2015.

But Pouncey had earned that designation in 2011 and 2014 (he was a second-team All-Pro in 2010 and 2012), so he's returning as much more than just a designated tone-setter.

"He's the best," DeCastro said. "It's one of those things you can talk about, and we tell you guys (in the media) all the time, but he's a special, special player.

"He makes us all better."

That should be good news for Alejandro Villanueva, who has been steadily improving ever since taking over as Beachum's replacement at left tackle.

Villanueva started 10 regular-season games and two playoff games in 2015 after spending the previous season on the practice squad.

"You can see it from his first year to this year going in," DeCastro said of the progress Villanueva has demonstrated. "Even the first game he started to the last game (last season), you could tell a major difference.

"He's going to keep getting better because he's relatively young."