The rookie wall isn't a tangible barrier. It's not something you see coming, leap over or otherwise navigate. It's just something in your mind.
But, invariably, it's something every rookie has to fight through in his first NFL season, especially when he starts to look to the end of the college football regular season, which wraps up this weekend, and sees his former teammates getting away from the game for a while.
That's something the Steelers have to remind themselves of when dealing with the two rookies, linebacker T.J. Watt and wide receiver JuJu Smith-Schuster, who have been integral parts of their 8-2 start to this season.
"Largely, if you look at your calendar, the seasons that they’re used to are coming to a close," Mike Tomlin said. "They’re getting ready for finals. They’re transitioning to bowl prep, etc. etc. Guys like (Watt) and JuJu and others, they’re moving into uncharted territory. It’s uncharted for them, but it’s not uncharted for us. We’ve been in these circumstances before. We’ve been in these circumstances helping people in their position before, so we’ll make it as tolerable for those guys as we can."
Youthful exuberance, after all, can only carry you so far, though Watt and Smith-Schuster, the team's top two picks in this year's draft, both have plenty of that to spare.
Watt celebrates each big play he makes -- such as this blocked field goal in last Thursday night's 40-17 win over Tennessee -- with great aplomb. You know when he has made a play:
The same goes for Smith-Schuster, who turned 21 on Wednesday. He's the youngest player in the NFL, and many times it shows, not in his play, but in the child-like enjoyment he gets out of the game.
He's been a driving force behind the team's choreographed touchdown celebrations, including such things as playing hide-and-seek with Le'Veon Bell after a touchdown or getting everyone together for an imaginary game of dice in the end zone following a Martavis Bryant touchdown against Minnesota earlier this year.
"It's just something that makes you smile and have fun," Bell said. "JuJu just has fun with the game."
One thing that makes it much more fun is winning. The Steelers have won their past five games entering Sunday's meeting with Green Bay (5-5) at Heinz Field and sit tied for the best record in the AFC with New England.
How they have been winning has helped keep the full attention of the rookie players.
"We’re not only winning, we’re winning in a whole lot of different ways," Watt told me. "It would be one thing if we were blowing teams out or just winning close games. We’ve seen all different aspects of winning, so I think that will help us down the road. We’ve seen we can come back from down or up and just stay in control of a game. We’ve really had a vast majority of situations we’ve been through."
But they're putting in a season that is not just demanding physically, but mentally, as well. Most players who are eligible or declare early for the NFL draft -- as both Watt and Smith-Schuster did this year -- leave school after the fall semester ends and the college all-star games are completed to begin training for the NFL Scouting Combine.
If things hadn't become more like a job in the big-money world of college football, the long days spent training in preparation for the combine certainly would have driven that point home. And then comes learning a new playbook, moving to a strange city and becoming acclimated to the pro game.
"I would have liked to have seen my face when they handed me the (defensive) playbook," defensive end Stephon Tuitt told me. "It was thicker than anything I'd ever read."
But Watt and Smith-Schuster have not only taken in all of that information, they have thrived. Watt has played 455 snaps, or nearly 75 percent of the team's defensive plays. That number would be higher had he not missed most of Week 2 and all of Week 3 with an ankle injury. Despite missing time, he has recorded 31 tackles, four sacks, an interception and a blocked field goal. He also has six quarterback hits and five passes defensed, showing he's a complete player.
At times, it's easy to forget he's a rookie. At least for some.
"No, I remember just about daily that he’s a rookie," Tomlin said. "There are things that go on between he and I that remind me that he’s a rookie. I’m glad that it doesn’t show up as clearly to you. He and all those guys are walking a journey that he hasn’t walked before."
But having two older brothers who also play in the NFL -- J.J. and Derek -- has helped Watt, as well. He not only has his teammates to rely on, but can also lean on the experiences of his brothers to help prepare him for the grind of an NFL schedule.
"He’s coming from a family where he has J.J., he has Derek. They’ve been in his position before," Arthur Moats told me. "They can tell him how to handle it. Ultimately, if you don’t talk about it and everybody just keeps on hitting the gas, then you don’t have to worry about it."
Having that support system in place and knowing what to expect are a couple of things that helped Watt get into the starting lineup early with the Steelers. His talent and ability have kept him there.
The Steelers also knew they had to get him a lot of experience to be prepared for the regular season. So not only has he played a lot of snaps in the regular season, he also did so in the preseason. Seeing all that playing time could be taking a toll. He has just seven tackles and no sacks in the past three games.
"I don’t think I’m hitting a wall," Watt told me. "It is a long season. Your body takes (a lot). But there’s a lot involved with what we’re trying to do here is special and we have the group to do it. So there’s no time to step back and say, ‘Holy cow, this is a lot going on.’ This is the time to push through whatever you’re going through and keep going."
Smith-Schuster's production, meanwhile, has seen an uptick in recent weeks, though he didn't get as much playing time early in the season as Watt.
"It's a lot different, you play more games and the season's a lot longer," said Smith-Schuster. "But you've just got to keep things the same."
Smith-Schuster has played 479 snaps, just under 70 percent of the team's offensive plays. He has 33 receptions for 552 yards and five touchdowns but has done his best work of late. He has 16 receptions for 337 yards and two touchdowns in the past three games.
The Steelers expect both players to finish strong, largely because the team has more experience dealing with rookies in the lineup in recent years. What once never happened -- rookies playing a major role, especially on defense because of that massive playbook Tuitt mentioned -- has now become the norm.
Last season, for example, corner Artie Burns and safety Sean Davis both played more than 70 percent of the team's defensive snaps, while nose tackle Javon Hargrave logged nearly 500 snaps.
But, like last season, when the Steelers won their final seven regular season games to finish 11-5 and advance to the AFC Championship, there is no time for a late-season letdown, not with the goal of getting home field advantage throughout the playoffs in sight.
"It’s a lot easier when you’re winning," Moats said. "Shoot, just coming to work every day is easier when you’re winning. Years past, you drop two games here or there, that sucks. When you’re able to put a string of wins together, it makes it easier to come to work."