After just four practices, there is no question Lane Kiffin is running things a bit differently than Pete Carroll.

Practices, while still up-tempo, are more intense. Players touch every line in sprints. If someone is out of line or makes an unforgivable mistake, that player runs a lap, regardless if it’s Matt Barkley or a walk-on receiver.

Not everyone is allowed in practices either. Unlike in the Carroll days, when pretty much all you had to do was show up with a photo I.D., security is more noticeable and enforced.

Kiffin doesn’t tweet a “song of the day” or hold his players’ hands and sing “Kumbaya.” He hasn’t had Will Ferrell come charging through Howard Jones’ gates dressed in a speedo and an Ironman top. In essence, Kiffin is all business and all football.

Ironically, it’s the latter part of that statement that seems to be hurting the Trojans. Before the first week of spring practice ended, more than a dozen players had sat out at one time or another with injuries. Here are the leads to the two Daily Trojan articles written after the Thursday and Saturday practices last week.

Thursday: “Day two of the Lane Kiffin era was nearly identical to day one — lots of second teamers, lots of intensity and a heavy emphasis on discipline.”

Saturday: “With injuries decimating the roster and a quarterback competition keeping the spring interesting, it was defense, not offense, that characterized this Saturday’s third football practice of the spring season.”

The common theme among these two sentences is injuries. Second teamers were playing Thursday because many starters couldn’t, as was evident Saturday.

This begs the question: Are Kiffin’s practices too tough, or were Carroll’s practices, while still hard-hitting, too relaxed?

Now, it must be noted some of the players are on the disabled list for reasons totally unrelated to practice. Redshirt junior tight end Rhett Ellison has mononucleosis and could miss all of spring practiceand redshirt junior center Michael Reardon is in a neck brace for injuries suffered during an ATV accident a few weeks ago.

Regardless, at least 10 players sat out Saturday’s scrimmage, the first practice in full pads, because of injuries including freshman running back Dillon Baxter (quad), safety Marshall Jones (neck), redshirt sophomore offensive linemen Matt Kalil (hip) and junior tight end Blake Ayles (ankle).

During USC’s first weekend scrimmage last year, there weren’t nearly as many players watching from the sideline. Taylor Mays barely played because of dehydration and Drew McAllister and tight end Anthony McCoy had hamstring injuries, but other than that, the team was healthy.

This spring, just four practices in, USC has been forced to go with many backups, especially at tight end. With USC’s top two returning tight ends, Ayles and Ellison, both out with injuries, the two players on the top of the team’s depth chart are two former wide receivers: senior Jordan Cameron and senior David Ausberry. They will both continue to get reps at tight end because, as Kiffin said Thursday, “we just don’t have the numbers.”

Some players are choosing to play despite injuries. Senior center Kristofer O’Dowd has been playing with a knee injury he sustained Thursday, and sophomore linebacker Devon Kennard is playing with a cast on his right wrist.

“It was a very physical, very long practice, but guys need to learn to get hurt and continue to play,” Kiffin said Saturday.

O’Dowd certainly got Kiffin’s message.

“Being injured means you can’t do anything — you’re out. Being hurt means, OK, you’ve got a knick-knack, but you can play through it,” he told the Los Angeles Times Saturday.

I like the energy, discipline, old-school toughness and business-like attitude Kiffin brings to the team. As much as I’ve enjoyed watching Carroll’s teams dance on the sidelines, break out in song in team meetings and joke around, something has been missing from the team over the past few years.

During the last few years of Carroll’s tenure, it felt almost like the team expected the trophies to be handed to them. It seemed as if they felt entitled.

Kiffin is making sure nobody feels entitled to anything and that’s what has been missing from USC’s past teams.

“There’s a definite emphasis on toughness,” Kennard told the Los Angeles Times. “We’re trying to go out there and bang as a defense and rekindle something we didn’t have last year.”

So while the injuries stockpile for the Trojans, it’s doubtful Kiffin will change his ways. If USC goes out and wins the national championship next season, it won’t be because of the glitz and glamour Trojan teams had in the past. It will be because of the toughness and new attitude Kiffin instilled in this squad.

He’s not too tough. And toward the end of his tenure, Carroll just wasn’t tough enough.

“Spittin’ Sports” runs Wednesdays. To comment on this article, visit dailytrojan.com or e-mail Kenny

at klegan23@gmail.com.