USC football goes full speed – even without pads

USC players have spent this week practicing in helmets and shorts – they won’t strap on pads until Sunday night – but that doesn’t mean they have been playing touch football.

Linebackers have flattened receivers coming across the middle. Running backs have ping-ponged between defenders and fallen hard. The linemen have gone at each other ferociously.

Coach Pete Carroll talks about “a fine line” in letting his team compete during workouts without unduly tempting injury.

No one knows how fragile that balance is better than a visitor to practice this week, former USC quarterback and new Avengers Coach Pat O’Hara.

In the summer of 1989, O’Hara, who had waited patiently behind Rodney Peete, finally won the starting job. In the last scrimmage of training camp, he rolled to his left and was hit by several players.

The ligaments in his right knee tore and the tibia was broken. Todd Marinovich became the starter.

Almost 20 years later, watching the Trojans practice, O’Hara cringed at seeing linebacker Rey Maualuga knock down tailback Joe McKnight.

“I’m like, ‘I hope Joe gets up,’ ” O’Hara said.

Carroll defends his practice tempo, saying that it teaches players to compete and to handle themselves at full speed, a lesson that could preclude injuries down the road.

This week, he made a believer out of O’Hara.

“I was so jacked up leaving practice,” the Avengers coach said. “They’re No. 1 because of that competitiveness.”

 david.wharton@latimes.com