USC quarterback Matt Barkley causes a stir with his tweet

Matt Barkley said Monday it was nothing personal.

USC was off last weekend because of an open date, but the Trojans’ sophomore quarterback created a social-network stir with a post on his Twitter feed in the aftermath of Cain Velasquez’s victory over Brock Lesnar in the Ultimate Fighting Championship heavyweight title fight Saturday.

Barkley, leader of the team preparing for a game this week against top-ranked Oregon, tweeted: “Wow, Brock just got rocked! Lesnar is to Oregon as Velasquez is to SC. Lezgo.”

The post was deleted shortly thereafter, but not before it was retweeted, riling Oregon fans and, presumably, Oregon players.

USC is a seven-point underdog against the unbeaten Ducks.

“That had nothing to do with Oregon,” Barkley said after practice. “I just got fired up thinking about my teammates.

“It had to do with kind of being an underdog in a big fight, like we’re going into. Everyone, of course, takes it out of context and blows it up. But that was about us and about our team and the adversity we’ve been through.”

Tackling a big issue

With Oregon’s nation-leading offense coming to the Coliseum, USC Coach Lane Kiffin relaxed his “no-tackling” practice policy and put cornerbacks and linebackers through tackling drills, mainly against the second-team offense.

Kiffin said poor tackling has been “game-changing” for the Trojans.

“If we can tackle at all in the secondary, we’re 7-0 right now,” said Kiffin, whose team lost to Washington and Stanford on last-second field goals.

The coach said he was not surprised by some of the players’ struggles to wrap up ballcarriers.

“It’s rusty,” he said of the Trojans’ tackling. “You don’t all of a sudden tackle well when you haven’t all year. . . . So, hopefully it will pay off.”

Speed game

The Trojans are preparing for an Oregon offense that plays at a breakneck pace and averages a nation-leading 55 points a game.

“You just have to stay alert and make sure you’re lined up right,” safety T.J. McDonald said recently.

Oregon zipped past the Trojans for a 47-20 victory last season at Autzen Stadium. The Ducks are playing even faster in Coach Chip Kelly’s second season.

“It’s not even close,” Kiffin said. “They’re much better in the system. . . . Going into his second year, I imagine his staff understands his tempo and what he’s trying to get done, and you can see it by what they’re doing.”

On lookout for No. 1

USC played 27 consecutive games as the nation’s top-ranked team during Kiffin’s first stint with the Trojans, as an assistant.

Saturday’s game will be his third coaching against a top-ranked team. Tennessee lost to Florida and Alabama last season when each was ranked No. 1.

“You feel how focused your players come to work because they have a chance to play the No. 1 team . . . that’s why what was done here before was so phenomenal,” Kiffin said.

Line getting healthy

The benefit of an open date was obvious along the defensive line as end Wes Horton practiced for the first time since suffering a back injury against Washington State on Sept. 25.

Nick Perry, nursing a high ankle sprain since training camp, appeared to move better. Even defensive line coach Ed Orgeron, who had foot surgery a few weeks ago, left his cart behind and walked the practice field.

“I think that our D-line is ready to go for the first time this year,” Kiffin said.

Quick hits

Linebacker Malcolm Smith (knee) and tailbacks C.J. Gable (knee) and Dillon Baxter (toe) did not practice. Kiffin said he hoped Smith and Baxter would return Tuesday. Gable said he planned to play Saturday.

gary.klein@latimes.com

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