UNIVERSITY PARK — The whistle blows and Penn State’s offensive linemen are summoned to the opposite end of the practice field.

Leading the group is No. 65, a 6-foot-3, 300-pound sophomore from Pittsburgh. Miles Dieffenbach trots the 80 yards, reaching the spot of the next drill five seconds before his line-mates.

There’s sound reasoning behind Dieffenbach’s nimble feet and active motor. He’s adept at another sport that requires precise footwoork.

Dieffenbach’s father, George, has coached tennis at Pitt since 1975. And, yes, his big son plays the family sport.

“It was my main sport until about seventh or eighth grade, then I really had to focus on football,” Miles said. Smart move.

Dieffenbach opened the summer competing with junior Mark Arcidiacono for the starting left guard job. Coach Bill O’Brien revealed Thursday that Arcidiacono has suffered a foot injury, which means Dieffenbach will start the Sept. 1 opener against Ohio University at Beaver Stadium.

“Miles has had a really, really good training camp,” O’Brien said. “He has picked up where he has left off after spring practice.”

Dieffenbach left the spring in good physical and mental shape. The turmoil of the past month, which included major NCAA sanctions and player defections, had no impact on Dieffenbach or Penn State’s other top linemen. The entire group stayed together.

That includes senior center Matt Stankiewitch, one of Dieffenbach’s mentors. Dieffenbach operated as Stankiewitch’s backup last season.

Dieffenbach said moving from center to guard is no big deal. The center, after all, has major responsibilities, ranging from starting plays to communicating defensive fronts.

O’Brien and offensive line coach Mac McWhorter moved Dieffenbach to guard shortly after their arrival last winter. McWhorter, who coached numerous agile linemen at Texas, has a theory about centers: they must be ready for everything, including a position switch.

“Center is harder to play than guard because there are a lot more mental aspects of it,” McWhorter said.

“Plus, you have that ball between your legs and you have to do something with it to start the play. The center is the quarterback of our offensive line. He makes the calls for us. Playing guard and center, you play right beside each other. We like for them to be interchangeable.”

Dieffenbach has noticed the impact of all those forehands, backhands, volleys and serves at guard. The position requires no center-quarterback exchange. The first move must be a bold one. The faster a player exits his stance, the more space he clears. Powerful feet are essential.

“You have to have good quickness and explosiveness getting off the ball and good lateral quickness,” Dieffenbach said. “It definitely fits myself as a player.”

Dieffenbach has been surrounded by agile linemen throughout his entire career. He attended Fox Chapel High School, which competes against the WPIAL’s Quad-A brutes. His high school coach, Bryan Deal, is a former member of Pitt’s football staff who led Dublin Scioto High School to an Ohio state title.

Penn State will rely on former WPIAL standouts to replenish an offensive line that lost four starters. Tackles Adam Gress (West Mifflin) and Mike Farrell (Shady Side Academy) are also western Pennsylvania products. Gress entered training camp as the first-team right tackle, although he has played left tackle for part of training camp because of redshirt freshman Donovan Smith’s hamstring injury. O’Brien said that Farrell, a senior, also factors into this fall’s plans.

Junior John Urschel, who hails from western New York, is the starting right guard. Stankiewitch attended Blue Mountain High School in Pennsylvania’s gritty Anthracite Region.

“We are meshing together really, really well,” Dieffenbach said. “We really have a chance to do something special up front and help the team run the ball and protect the passer. I think we are going to be really good.”

Still, Dieffenbach has one complaint regarding his teammates. He can’t find quality tennis players on the roster.

“Nobody on the team plays well,” he said. “Some come out and hit balls. That’s about it.”

Guy Cipriano can be reached at 231-4643. Follow him on Twitter @cdtguy