EUGENE, Ore. -- No more rookie excuses for Thomas Tyner.

Oregon's sophomore running back is ready to live up to the expectations that were heaped on him when he joined the Ducks last year.

"It's time to grow up," he said. "It's time to step up and do it big."

As a freshman Tyner was third on the Ducks with 711 yards rushing, and he scored nine touchdowns. He steadily improved and had a breakout in the Civil War rivalry game against the Oregon State Beavers, with 22 carries for 140 yards and a score in Oregon's 36-35 victory.

OREGON 2014 SCHEDULE
Aug. 30 vs. South Dakota
Sept. 6 vs. Michigan State
Sept. 13 vs. Wyoming
Sept. 20 at Washington State
Oct. 2 vs. Arizona
Oct. 11 at UCLA
Oct. 18 vs. Washington
Oct. 24 at California
Nov. 1 vs. Stanford
Nov. 8 at Utah
Nov. 22 vs. Colorado
Nov. 29 at Oregon State
The Ducks finished the season 11-2 with a victory over Texas in the Alamo Bowl. This year they're ranked No. 3 in the nation heading into the opener Aug. 30 at home against South Dakota.

Tyner says he's ready, having matured as a player since last season.

"Now it's just more natural. Last year I think was I was thinking way too much," he said. "Now I'm just thinking about the play, and what I have to do in the moment."

Oregon's expected starter at running back this season is Byron Marshall, the Pac-12's top returning rusher who ran for 1,038 yards and 14 touchdowns last season.

Tyner is competing in fall camp with promising freshman Royce Freeman, considered one of the top prospects in the nation out of high school.

Freeman, who is from Southern California, also had offers from Alabama, Florida, Florida State, and Stanford before settling on Oregon. He ran for 2,824 yards and 41 touchdowns as a high school senior, drawing comparisons to former Ducks LeGarrette Blount and Jonathan Stewart.

Like Freeman, Tyner was a star in high school.

Nicknamed Dash, Tyner was a homegrown recruit from Aloha High School, west of Portland. He rushed for 3,415 yards as a senior, setting a new single single-season rushing record for the state. He scored 47 touchdowns, 43 on the ground.

On his 18th birthday his senior year, Tyner smashed state records with 643 yards rushing and 10 touchdowns in an 84-63 victory over Lakeridge High School.

It was the third-most rushing yards ever for a prep player, behind John Giannantonio's record of 754 yards in a game for Netcong High School in New Jersey in 1950, and Paul McCoy's 661 yards rushing for Matewan High School in West Virginia in 2006.

Scott Olmos | USA TODAY Sports Images
All eyes were on him as a freshman last year, but Tyner admits that at times he wasn't fully engaged. Because he's from Oregon, he went home a lot. And everything about football was new — he went from a more pro-style high school offense to the Ducks' speedy spread-option.

In addition to spending more time in Eugene this season, the 5-foot-11, 215-pound back is focusing on improving physically.

"This year I'm working my conditioning," he said, adding with a smile: "I've been working on getting stronger — and getting meaner. "

Oregon coach Mark Helfrich said he's seen Tyner's improvement — but he still has a ways to go.

"The guy is an excellent protector and an excellent blocker when he's fully cut loose. He just needs to have a little more confidence in what he's doing," Helfrich said. "Part of that is experience."

Because of its option offense, Oregon has become known for its running backs in recent years, including LaMichael James, Kenjon Barner, Blount and Stewart. Tyner would like to follow their lead.

"I've got a lot to work on," Tyner said. "There's been a lot of great running backs at Oregon and they've all stepped up. I think it's time for me to step up too."