CLEMSON, S.C. -- Dabo Swinney keeps a nameplate sign on his office bookshelf that reads simply: "Can't Do It." The apostrophe and the "t" after "Can" are crossed out.

Clemson's gregarious eighth-year head coach has made a living out of checking off a series of milestones many assumed his Tigers couldn't do -- post five straight 10-win seasons; beat bowl foes like LSU, Ohio State and Oklahoma; and most recently, reach the College Football Playoff championship game. Having posted a school-record 14 wins last season and played toe-to-toe with mighty Alabama, the next "can't" for Clemson to conquer is "can't do it again."

"Without the consistency we had the last five, six years, everyone would just kind of say, well, they had a good year. They had a good team. I don't want to have a great team, I want to have a great program."

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With Heisman finalist and championship game extraordinaire Deshaun Watson returning at quarterback as well as 1,527-yard rusher Wayne Gallman, top receiver Artavis Scott, postseason standout Hunter Renfrow and All-ACC tight end Jordan Leggett, external expectations may finally catch up to Swinney's this preseason. Clemson may trail only Alabama in the preseason polls.

But there's reason for skepticism too. Six key defensive players -- All-American defensive end Shaq Lawson and bookend Kevin Dodd; All-American safety Jayron Kearse and fellow starter T.J. Green; lockdown cornerback Mackensie Alexander and linebacker Travis Blanks -- all turned pro early. Which means for the second straight year, coordinator Brent Venables must replace the large majority of his starting lineup.

But Swinney, of course, rarely lacks for confidence. Mocking the ubiquitous "returning starters" statistic, he took a printed Clemson spring prospectus from the table and lifted it in front of him as a prop.

"The game's not played on paper," he said. "If it was, I would go to midfield, I'd meet up with the other coach, I'd show him my recruiting stats, my Xs and Os, the crowd would ooh and aah, and they'd declare a winner.

"Most people focus on what's gone. I don't control that. I control who's here. I know the talent we have on our roster."

Clemson plays its spring game Saturday. After spending a day visiting the program and attending practice, here are my biggest takeaways about the state of the Tigers.

They're huge on the defensive front

Clemson is loaded at defensive tackle. Or as Swinney puts it, "We're going to be freakish inside." Senior Carlos Watkins and junior Scott Pagano are technically the returning starters, but 6-foot-4, 308-pound sophomore Christian Wilkins is the group's rising star. Venables likens him to former USC standout and top-10 draft pick Leonard Williams. Like Williams, Clemson may use the versatile Wilkins at both tackle and end.

"That's very unique to be able to play inside and out and play it well," said Venables. (FOX Sports' Bruce Feldman profiled Wilkins in March.)

Meanwhile, massive 6-foot-5, 340-pound early enrollee Dexter Lawrence -- most services' No. 2 recruit in the country last winter -- is already seeing reps with the first team. "He's a manchild," said Watkins. "... I ain't ever seen anything like it. No offensive lineman can move him. He does what he wants to do."

Defensive end is a question mark

Conversely, there's no obvious star at end like Lawson and Dodd (or Vic Beasley and Grady Jarrett before them). That's why coaches are experimenting with Wilkins there. Sophomore Austin Bryant, who played most of the semifinal win over Oklahoma, and redshirt freshman Clelin Ferrell are the leading candidates.

Both Swinney and Venables are hopeful incoming freshman Xavier Kelly, a top-100 recruit, can contribute right away.

Mike Williams might be better than ever

Receiver Mike Williams is back from a scary season-ending neck injury in last year's opener when he crashed into the base of a goal post while diving for a catch. As a sophomore in 2015, Williams averaged 18.1 yards per catch for 1,030 on the season. "He looks better than I've ever seen him," said co-offensive coordinator Tony Elliott. "You haven't seen any ill effects from the injury at all."

Williams rejoins an already crowded receiving corps that includes Scott (93 catches for 901 yards in 2015), Leggett (40 for 525), Renfrow (33 for 492, including seven for 88 and two TDs vs. Alabama) and Ray-Ray McCloud (29 for 251). Clemson will also likely get back Deon Cain (34 for 582), who's been suspended since shortly before the Orange Bowl.

Secondary is an issue

Clemson's biggest question is its secondary. The Tigers have lost six defensive backs since the national championship game -- Alexander, Green and Kearse turned pro; cornerback Adrian Baker tore his ACL; one backup transferred and another was dismissed. That leaves returning starting CB Cordrea Tankersley and a bunch of unproven contenders. Junior Ryan Carter is the best bet to start opposite Tankersley while senior Jadar Johnson and sophomore Van Smith figure to be in the mix at safety. After that, there could be a lot of youth.

"You just hope we recruited well there," said Venables.

Watson is impressive off the course too

Deshaun Watson is impressive on and off the field. Strangely, this will be the Clemson star's first, and probably last, spring game. He hadn't arrived on campus yet for 2014's and missed 2015's while recovering from his knee injury. Given how entrenched he is on the national landscape, it's crazy to realize he's not yet been in college for two full years.

Even more so, he's not that far from graduating.

The junior-to-be is taking a staggering seven courses -- 19 credit hours -- this semester to stay on track to graduate this December. "It's a lot of late nights and early mornings, but it's something I just wanted to do," he said. "I had the opportunity, so why not do it?"

On the practice field, Watson is working on developing more consistent footwork. While hard to nitpick a sophomore season in which he became the first FBS quarterback ever to throw for 4,000 yards and rush for 1,000, Swinney points out that he did throw 13 interceptions and personally took six sacks.

"At the end of the day, he had an unbelievable year, he's third in the Heisman for a reason," said Swinney. "But how do we get better? It's being fanatical about your fundamentals, your footwork, your decision-making."

Watson strikes you as the kind of guy who doesn't need much prodding when it comes to self-improvement.

As for the Tigers as a whole, the pieces are there for another playoff run. And Swinney is not the type of coach to try and pump the brakes when it comes to expectations.

"My big message has been, we're not going anywhere," said Swinney. "We're built to make a run."