Lane Kiffin is not happy with practice

The week started well enough, USC Coach Lane Kiffin began.

His football team even practiced “very well” Tuesday and Wednesday, he continued — and this praise came after he expressed absolute disappointment in the Trojan’s 17-14 victory over Virginia last Saturday.

But as this week wore on, progress seemed to go backward, culminating Thursday with a showing that left Kiffin concerned as the team heads to Minnesota for Saturday’s game.

“We’ve got a long ways to go,” he said. “They need to understand that this is a very serious game and not take this opponent lightly because of what happened last week [when Minnesota lost, 41-38, to South Dakota], which doesn’t mean anything Saturday.”

Quarterback Matt Barkley said the players “don’t think it’s going to be a cakewalk going in,” but he called Thursday’s practice particularly “sloppy.”

For him and the rest of the offense, it was, as near the end a few of Barkley’s passes were intercepted, either directly or on tipped passes, including two by safety T.J. McDonald.

But Barkley, who has thrown seven touchdowns without an interception this year, said much of the offensive hiccups came as a result of new plays being installed.

“Got all those mistakes out of the way before they happened in the game, which was good,” Barkley said. “But overall, we added a lot of new things this week, and I’m happy with how we responded. Guys are knowing their stuff, so that’s good.”

Running back Marc Tyler, who Kiffin said would start against the Gophers, said he’s also ready to carry the ball more if asked.

On the flip side, USC’s defense looked sharp, as Kiffin said it has all week. Forcing turnovers, which the team has only done once all year, has been an emphasis.

“We’ve been on the field way too much not to have [forced] as many turnovers as we should,” cornerback Shareece Wright said.

Still kicking

Kicker Joe Houston is looking to achieve another milestone against Minnesota.

The senior’s first career field goal provided what proved to be the deciding points in last week’s 17-14 victory over Virginia.

Now, if called upon, he is confident he will convert for the first time in front of a hostile road crowd.

Houston, who didn’t attempt a field goal in the opener at Hawaii, missed a 48-yard third-quarter attempt against Virginia before making a 34-yard field goal with about eight minutes to play.

“I wasn’t holding my head high,” he said this week. “I went one for two. If we play a good team, that could cost us the games. I have to get better.”

Quick hits

Defensive linemen Nick Perry (ankle) and Armond Armstead (shoulder) were listed as limited during Thursday’s practice, but each practiced with the first-team defensive line at times and it looked likely they will play Saturday. …Tight end Jordan Cameron, who suffered a concussion against Virginia, was involved in a considerable amount of the non-contact passing drills and seemed a favorite target of Barkley despite being listed as limited. … Reserve linebacker Simione Vehikite was held out of practice. … Defensive line coach Ed Orgeron, who suffered a broken foot last week at practice and was on crutches all this week, will coach from the sideline Saturday rather than from the booth, Kiffin said.

baxter.holmes@latimes.com

Times staff writer Gary Klein contributed to this report.