STATE COLLEGE, Pa. -- For two years, Saquon Barkley has made jaws drop with breathtaking runs, from the time he announced his presence to the world with a leap over a Buffalo defender early in 2015 through his dazzling 79-yard touchdown run in the Rose Bowl against USC to end the 2016 season. He has accumulated 3,135 yards from scrimmage over two seasons to make himself a preseason Heisman Trophy candidate entering 2017, with growing speculation about how early he could be selected in the NFL Draft and where he'll rank among Penn State's greatest running backs when he leaves Happy Valley.

The scariest thing for opposing defenses is that last year's performance may have merely been a preview, because they've yet to see the best of Barkley. The main event is still to come in 2017, with assistance from the long-awaited development of the five blockers in front of him.

"One of the things that I said in the first meeting together here a couple days ago is that last year we were good enough," second-year offensive line coach Matt Limegrover said on Saturday. "I don't think we were necessarily a really good offensive line. We were good enough to score the points that we did and to have the winning streak, contributing from an offensive perspective and some of the things that Saquon was able to do. But we need to be a really good, solid, consistent group and go out there and really grind it out and give these wonderful athletes that we've accumulated here, give them a chance to exhibit all their skills."

The offensive line flashed potential but had a lot of youth and moving parts, making it understandably inconsistent. NCAA sanctions impacted the offensive line more than any other position group, and the unit is just now returning to full strength.

Two years ago, Barkley's sparkling debut season featured endless frustration for Penn State's offense, as quarterback Christian Hackenberg repeatedly took hits for the second season in a row and the unit ranked 78th in yards per play. Last year, with Limegrover building the line and new coordinator Joe Moorhead calling the plays under head coach James Franklin, Penn State morphed into an exciting big-play offense, leading to a nine-game winning streak and a Big Ten championship. But there were negative plays and struggles on third down, and the young line wasn't quite ready to consistently play up to the level of the skill-position players and quarterback Trace McSorley.

Barkley won Big Ten offensive player of the year with the offensive line still being a work in progress. In 14 games, Penn State started seven offensive line combinations. By the Rose Bowl, partly because of injuries, that line featured a senior (Brian Gaia), a sophomore (Chasz Wright) and three freshmen (Ryan Bates, Connor McGovern, Steven Gonzalez) paving the way for Barkley's 194-yard day in a 52-49 loss to USC. The game featured an encouraging performance from such a young line, but Barkley's memorable touchdown run was accomplished in large part by himself as he bounced it outside and made several cuts to burst into the open field.

"Put it in air quotes, the 'trouble' with having a guy like Saquon in the backfield is he can end up making [the line] look better than it really is," Limegrover said of Barkley's impact on the line's reputation. "So what happens is he goes and gets 200 yards, and we rush for 250, and everybody wants to pat the guys on the back, and I look at the film and go, 'That was a couple long runs on broken plays' … so the perception and the reality, you gotta temper the perception and make sure they understand and not get crushed by the reality."

Barkley finished 24th nationally in rushing yards per game, racking up 272 carries for 1,496 yards and 18 TDs, in addition to catching 28 passes for 402 yards and four TDs. He tallied those numbers despite a slow start for him and the offense as a whole, as defenses loaded the box against him before the passing game morphed into a big-play machine to spark the win streak. He had five 100-yard rushing games, three of which featured at least 194 yards, although he had over 100 yards from scrimmage nine times because of his receiving.

Even in games when he was contained, Barkley typically made some kind of head-turning or game-changing play, like the 25-yard touchdown run for the win in overtime against Minnesota, a turning point in the Nittany Lions' season three weeks before their program-changing win over Ohio State.

With the team's highest preseason expectations since 1999 -- Penn State is No. 6 in the preseason coaches poll -- the line has legitimate depth and competition featuring experienced players and highly regarded young players. It's the biggest reason to believe that all the preseason hype is justified and that this team will avoid regressing. For the first time, Barkley could run behind a line that grows into a strength, with six returning players owning starting experience plus a few highly recruited young players who could make an impact, too.

"They've grown so much," running backs coach Charles Huff said. "Obviously, playing young guys has helped. But last year they were the unsung heroes of what we did. Building on that, they have a lot more confidence. Some of those guys are back. They're challenging the younger guys. The younger guys that redshirted last year are taking bigger roles."

A stabilized, more experienced and more consistent line is an enticing thought for an offense that returns Barkley, McSorley and a wealth of talented athletes, playing in Year 2 of Moorhead's offense. Barkley has fantastic big-play ability, but all of the above could allow him to be more consistent and efficient, as Penn State finds different ways to feed him the ball. Already a dangerous receiver, Barkley -- who says he's up to 230 pounds -- expects to be even more involved in the passing game as Moorhead tries to exploit the matchup advantages that the versatile and freakishly athletic junior tailback can create.

"Saquon, obviously, there's a lot of excitement, and rightfully so," Franklin said. "Once again, he's earned it. He's a special guy. But we've got a lot of guys that have special roles and have made tremendous impacts here. So we're going to use Saquon in every way we possibly can to give our team the best chance to be successful, short-term and long-term. And that's obviously running the ball. That's getting him more involved in the passing game because everyone is going to be focused on not allowing Saquon Barkley to beat them as a runner. And then also in special teams, as well."

After two seasons, Barkley is less than 1,400 yards away from setting the career rushing record at a school with a deep roster of star college runners. Since the NFL-AFL merger, no team has had more running backs selected in the first round of the draft than Penn State's nine. Led by 1973 winner John Cappelletti, Penn State has also had five running backs finish in the top five of the Heisman Trophy race. Barkley is already a strong bet to join the former group, and the growth of the line will put him in position join the latter group of Heisman contenders, too.

It's not just the athleticism and on-field talent that sets Barkley up for even bigger things in 2017. As anyone on the coaching staff will point out, Barkley is set up to succeed because of how he has handled the increased individual attention and because of his leadership ability, which has extended to his relationship with a line that has had many obstacles to overcome in the past few years. Limegrover said that Barkley buys donuts and candy bars for his blockers and "probably talks more to the offensive line than maybe I do," in terms of motivation.

"Sometimes you hold your breath when you have a guy like Saquon," Limegrover said. "What's it going to be like when the first time something goes wrong -- the fingers are pointing or, 'Hey, you didn't block for me well enough, or, 'I need more,' something like that. Never once has that crossed his mind. Quite honestly, he could have said that a couple of times last year, and I think that's what makes those guys say, 'Hey, let's make sure we give him every chance to be as successful as he can be.'"

By many measures, Barkley was already one of college football's most successful running backs last season. As Barkley became a national star amid Penn State's offensive resurgence, the offensive line showed flashes of what it is capable of doing with more seasoning. It's thus reasonable to expect the line to make another leap forward from 2016 to '17, and that increased experience and effectiveness up front will, in turn, allow Barkley to achieve even more than we've already seen.

How successful can Barkley be? Last year was only the beginning.

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