Anne M. Peterson / The Associated Press

EUGENE — One of the most notable numbers in the stat line of University of Oregon quarterback Marcus Mariota's stat line is zero. That is the number of interceptions he has thrown in the entire first half of the season.

The sophomore, who has become a top contender for the Heisman Trophy, has not had an interception in 233 pass attempts dating to last year, an ongoing Pac-12 Conference record.

Overall this season, Mariota has completed 100 passes for 1,724 yards and 17 touchdowns for second-ranked Oregon. He also has run for 426 yards and eight more touchdowns.

Ducks coach Mark Helfrich joked when asked if he remembered the last time Mariota threw a pick.

“Um, I don't know. I don't off the top of my head,” he told reporters, then added: “There was one in practice today.

“Marcus does a great job — good, bad or indifferent — of just kind of moving on and playing the next play.”

For the record, Mariota's last interception came in then-No. 1 Oregon's 17-14 loss to Stanford last Nov. 17, a defeat that dashed the Ducks' hopes for a shot at the BCS title game.

The streak of 233 attempts topped the string of 216 by USC's Brad Otton 1994-95.

This season, the mobile 6-foot-4 quarterback from Hawaii is averaging 287.3 yards passing per game and 71 yards rushing — for 10.4 yards per carry. He is ranked sixth nationally with an average of 358.3 yards in total offense per game, and he is No. 5 in passing efficiency at 182.40.

He has scored at least one touchdown via both the run and the pass in every game this season.

Known for his composure on the field, he also is trying to keep a level head about all the attention that has come his way off it.

“I wouldn't say I'm unaware, but I do my best not to pay attention,” he said. “I focus on coming into the facility and just working out and doing the best that I can and getting better every day.”

Entering last season, Mariota was a redshirt freshman who earned the starter's job over Bryan Bennett after a preseason camp competition that was mostly a mystery because the Ducks keep practices closed.

He went on to set the team's single-season record with 38 touchdowns (32 passing, five rushing, one receiving). The first freshman selected to the Pac-12's all-conference first team in 23 years, Mariota completed a school-record 68.5 percent of his passes.

Last weekend he completed 24 of 31 passes for 366 yards and three touchdowns in Oregon's 45-24 victory at then-No. 16 Washington. Mariota also ran 88 yards for a touchdown, earning Pac-12 player of the week honors.

He was similarly honored the week before when he set a school record with 42 points in Oregon's 57-16 win at Colorado. He passed for 355 yards and five touchdowns while running for 43 yards and two scores. The total of seven touchdowns matched the Pac-12 record.

“You have to make great decisions not to turn the ball over, and then you have to be really accurate with your throws and real careful with the ball,” Oregon offensive coordinator Scott Frost said. “You can be careful and not turn the ball over, but then you're not being productive either. So the combination of productivity and his ability to take care of the football has been impressive.”

The Ducks (6-0, 3-0 Pac-12) are the last undefeated team in the Pac-12 North after Stanford was upset by Utah last weekend. UCLA is the only undefeated team in the Pac-12 South.

Oregon will host Washington State (4-3, 2-2). The Cougars are coming off a 52-24 home loss to Oregon State last weekend.

This week in a practice the Cougars' scout team used receiver Drew Loftus at quarterback, which most assumed was a tactic for simulating Mariota's exceptional mobility.

Helfrich was asked whether he would be involved in an Oregon campaign to push Mariota for the Heisman this season.

“I think the best thing that anybody can do is play well as a team,” Helfrich said. “I think he understands that, and our team understands that. All those accolades and honors come as the result of that. Our best service to him and to our team is to prepare great, and then it allows him to play well.”