HARRISONBURG — When James Madison opens preseason practice Wednesday, the Dukes will officially begin the defense of their 2016 national championship.

Key members of the title-winning squad like running back Khalid Abdullah, linebacker Gage Steele and punt returner Rashard Davis have graduated, leaving opportunities for role players from last year’s squad, and newcomers, to make an impact this season.

Here are five potential breakout players to keep an eye on throughout the August training camp:

TE Nick Carlton

In 2016, no James Madison pass-catcher hauled in more touchdowns than tight end Jonathan Kloosterman.

His team-best seven touchdown receptions included a game-winning catch at Richmond, two against New Hampshire in the second round of the playoffs and one each in the quarterfinals, semifinals and national title game.

Kloosterman is back for his senior season, but because the Dukes lose three of their top four receivers from last year — Davis, Brandon Ravenel and Domo Taylor — the team will need more than 1,800 receiving yards worth of production the trio combined for to come from another source.

One source could be sophomore tight end Nick Carlton.

Senior quarterback Bryan Schor said JMU could use Kloosterman and Carlton on the field at the same time.

Carlton, a 6-foot-3, 234-pound Georgia native, had two catches for 41 yards last year.

“I think Nick Carlton had a really good spring and summer, so we’re excited to see what he could do,” Schor said. “He’s a talented young guy that runs routes really well and catches the ball exceptionally well, so we’re really excited to see what we can get out of him.”

RB Cardon Johnson

Senior running back Cardon Johnson isn’t a newcomer and has been an impact player before, but this is more about how the Warwick High School product bounces back from the Achilles injury he suffered last year.

Last month, Johnson said his goal was to take the field for JMU’s opener on Sept. 2 at East Carolina.

Second-year coach Mike Houston said everything he’s been told by the program’s athletic training staff is that Johnson’s rehab has gone according to plan.

“He’s tracking to be ready to practice,” Houston said. “And he’s tracking to be full-speed for game one.”

Punter Harry O’Kelly

It was a little bit of a surprise on National Signing Day when the Dukes inked Australian punter Harry O’Kelly.

The squad needed a punter with two-time All-Colonial Athletic Association pick Gunnar Kane having graduated. Last year, Kane was third in the CAA in punt average and landed 20 punts inside the 20-yard line.

If O’Kelly fares well during camp, the job will be his to start the season.

DL Simeyon Robinson

When Houston was asked who most excited him entering camp during last week’s CAA media day in Baltimore, the first name he mentioned was Simeyon Robinson.

“We’ve had guys completely change as a person,” Houston said. “But when I first got to JMU, Simeyon Robinson had a 2.0 GPA and was on the verge of being ineligible. He was out of shape, overweight and he couldn’t play a couple of snaps in a row.

“You look at him now, he’s chiseled up and got a 2.6 GPA. He’s turned his life around.”

Robinson made 10 starts last year and had 34 tackles to go along with 7.5 tackles for loss and four sacks.

LB Landan Word

JMU has the luxury of depth at many positions — quarterback, running back, defensive line, middle linebacker and cornerback — but one spot without as much is the outside linebacker position.

In the spring, Dukes sophomore Bryce Maginley took reps at outside linebacker with the first-team defense. Maginley was excellent on special teams for JMU last fall, registering a touchdown on a scoop-and-score against Sam Houston State in the playoffs, but he doesn’t have much experience on defense.

Virginia transfer Landan Word, who brings with him Atlantic Coast Conference game experience, could crack the starting defense in his first camp with the Dukes. Word will rep at outside linebacker after he played in 10 games and compiled 21 tackles and two sacks for the Cavaliers last fall.