From the moment RB Jonathan Dwyer arrived at St. Vincent College in Latrobe, Pa., for the start of Steelers training camp, you could tell something was different.
Yes, his 5-11, 229-pound body appeared more chiseled, as if "baby fat" miraculously disappeared on his 23rd birthday.
But to the Steelers' organization, the physical changes weren't the only thing that stood out.
"He's a young man that I believe is maturing," coach Mike Tomlin said during his weekly press conference. "Of course, he just turned 23. It's funny to say that a guy is in his third year and just turned 23, but he just did. There's a certain level of growth and maturity from a personal standpoint."
That's no accident. Dwyer said he made a conscious effort to mature -- not just as a football player but as a person.
"Just 'grow up and take care of business,'" Dwyer said of his offseason mindset. "Take care of things that are important to me, which is family and my job. Those two things are more important to me than anything."
It's possible Dwyer, a former All-American at Georgia Tech, will make his first career NFL start Sunday night when the Steelers open their season at Denver. Rashard Mendenhall just began practicing this week as he continues recovering from a torn ACL and Isaac Redman has a balky ankle that is leaving his status in question. Both, however, did fully practice Thursday.
If neither can go -- or if Steelers coaches determine that neither is at 100 percent -- Dwyer could start against the Broncos.
Dwyer definitely will be in uniform in Denver. He has dressed for only eight NFL games over two seasons. Seven came last season, when he had 16 carries for 123 yards, including a 76-yard run against Tennessee in his season debut Oct. 9.
Despite having a carry during only four different NFL games, Dwyer remains confident in his abilities.
"I just know what I can do, I know what I bring to the team," he said. "I know what my talents are and what my gifts are and how I play, so that's pretty much what I try to bring to the table, my playing style and just going out there and believing in what God's given me and just use it to my advantage."
New offensive coordinator Todd Haley, of course, can't speak to what Dwyer was like last season. But Haley noticed the way Dwyer would tutor young running backs during training camp.
"Everything I've seen is that (he's) a young, developing player who's made big strides from last year," Haley said. "You saw some real encouraging signs from a kid who's growing up and maybe realizes it's his third year and ... that becomes the make-or-break (season) at times."
Follow Steelers reporter Chris Adamski on Twitter @CBSSportsNFLPIT and @BuzzsawPGH.