UNIVERSITY PARK — He arrived late to work.

OK, Penn State coach Bill O’Brien entered the Lasch Building at 4:45 a.m. Monday. Players didn’t report until 30 minutes later for the 6:15 a.m. practice, the first of 29 on-field sessions before the Sept. 1 opener against Ohio University.

So nobody will deduct money from O’Brien’s paycheck. He, after all, started his workday before dawn.

But when he entered the Lasch Building to begin his first preseason practice as Penn State’s football coach, a captive group awaited.

“I couldn’t sleep last night for good reasons because I couldn’t wait to start practice,” O’Brien said. “I think I was the last one to arrive. Our staff was here at 4:30. They are going to be busting my chops.”

Early workdays? Coaches gently ribbing their boss?

O’Brien gladly accepted the loss of sleep and barbs.

For the first time since 1966, Penn State opened preseason camp with a new coach. The 42-year-old O’Brien, who replaced Joe Paterno in January, seemed recharged after two long weeks of mostly bad news.

Wearing an all navy blue outfit consisting of track pants, long-sleeve shirt and hat, O’Brien dangled a whistle below his mouth and watched more than 75 returning players practice on a hazy morning.

The team O’Brien guided contrasted the group he directed in Penn State’s last spring practice, the Blue-White Game on April 21. The Nittany Lions have lost 13 scholarship players, including eight in the past nine days, since the end of spring drills.

The recent departures are a product of NCAA sanctions levied July 23 against the school in the aftermath of the Jerry Sandusky sex abuse scandal. The sanctions allowed players to transfer without having to sit out a season.

The penalties are testing the program’s resolve. Running back Silas Redd (Southern California), wide receiver Justin Brown (Oklahoma) and kicker/punter Anthony Fera (Texas) were among the key pieces to leave last week.

O’Brien said he doesn’t anticipate losing more players, but few guarantees exist in his business.

“Every single day is a challenge and right now we take it day to day,” he said. “We are here for these kids. We are doing the best job we can for this football team, this football program, this athletic department and this university.”

O’Brien, the New England Patriots’ offensive coordinator last season, spent Monday working with the offense, a group returning just one full-time starter. O’Brien has an offensive background, so it’s not surprising he lurked behind quarterback Matt McGloin throughout the 30 minutes of practice opened to the media.

Standing behind an inexperienced secondary, defensive coordinator Ted Roof observed his first preseason practice at Penn State. Roof’s unit features stability because his front seven is loaded with experience and assistant coaches Larry Johnson (defensive line) and Ron Vanderlinden (linebackers) return. Roof, like O’Brien, wore long sleeves despite comfortable 60-degree weather. Roof coached at Auburn the past three seasons, so perhaps the start of this camp felt chilly compared to his recent ones.

O’Brien and Roof’s first preseason practice ended with a sign of unity as players gathered in a huddle and chanted “Penn State” before exiting the field. The day continued with meetings, film dissection and an evening practice for the program’s newcomers. First-year players begin assimilating into varsity practices today.

Veterans begrudgingly left the field Monday morning as video coordinators and graduate assistants hurried film into the Lasch Building. O’Brien met with reporters while assistant head coach Stan Hixon lobbed passes to juniors Shawney Kersey and Brandon Moseby-Felder, two players whose roles are expanding with Brown’s departure.

Hixon, who coaches the wide receivers, was throwing passes to players for the first time since the Blue-White Game. NCAA rules prohibit coaches from conducting summer workouts.

O’Brien and Hixon, who worked for the Buffalo Bills last season, are installing a pro-style offense, and camp escalates when two-a-days begin Saturday. Before reaching the weekend, Penn State must complete practice No. 2.

“Just like every team in the country, you only have 29 practice opportunities,” O’Brien said. “Every single day we come out here we can only do two things — you get better or you get worse. We’re trying to be more consistent (today) when we come out here.”

After the past two weeks, practice gaffes such as an interception or missed assignment aren’t turning O’Brien or his assistants sour.

“I’m very confident that the guys that are here are committed,” he said. “It’s day to day, but I’m confident in these guys. They got up at 5:15 and practiced. It wasn’t great, it wasn’t all pretty, but there were some good plays out here, and we just have to continue to get better.”

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