Byron Marshall embodies Oregon's ''Next Man In'' philosophy.
Called upon to take over last weekend against California when De'Anthony Thomas left after the opening kickoff with an ankle injury, Marshall ran for a career-best 130 yards and two touchdowns. He'll be tapped again this Saturday when the No. 2 Ducks (4-0, 1-0) visit Colorado.
Thomas is most likely to sit out against the Buffaloes because of the right ankle sprain he sustained in the 55-16 victory over the Golden Bears. The dynamic running back returned the kickoff 27 yards but slipped on the turf that was slick from a driving rain.
Thomas has been wearing a boot and running backs coach Gary Campbell told reporters earlier this week that the speedy junior's return was ''not going to happen'' against the Buffaloes (2-1, 0-1). Thomas leads the Ducks with 338 yards rushing and six touchdowns this season.
Marshall is ready to go, Campbell said. About the only issue he had against Cal was fumbling in the pouring rain, including on his first two carries.
''I liked everything about his game except for the fumbles of course. That was a lot due to the weather,'' Campbell said. ''But Byron stepped up and showed that he had the stamina to carry the load like I figured he would.''
Marshall, a sophomore from San Jose, Calif., rushed for 464 yards and four touchdowns last season, while a bulk of Oregon's carries went to Kenjon Barner and Thomas. Barner graduated and is now with the Carolina Panthers.
Much like Barner was a more-than-capable backup to LaMichael James until James went to the San Francisco 49ers, Marshall is proving he's a sturdy and dependable sub for Thomas. He has rushed for 326 total yards and four scores so far this season.
''My mentality never changes,'' Marshall said. ''My job is to be ready when they tell me to go.''
Freshman Thomas Tyner also contributed against California, with 13 carries for a career-best 94 yards, including a 21-yard touchdown run in the third quarter.
So far this season, Oregon is ranked atop all FBS-level schools with an average of 332.5 yards rushing per game. The Ducks are ranked third in total offense with an average of 599.3 yards a game, and second in scoring offense with 59.8 points per game.
For the first time in school history, the Ducks have scored 50 or more points in four consecutive games.
All of that is obviously a concern for Colorado coach Mike MacIntyre.
''They go really fast and they get all these different formations, and if you don't line up right then all of a sudden there's a big gap and they go so fast that they're gone,'' MacIntyre said. ''So you have to understand where to line up and hopefully we've practiced against ourselves enough, and we do fast speed periods, that we can line up correctly and then you have to tackle them in open space. That's what we have to do, so hopefully that's what we do.''
The Buffaloes are coming off a 44-17 loss at Oregon State last Saturday.
Colorado actually ranks atop the Pac-12 in rushing defense, allowing just 91.3 yards a game. Last weekend they allowed Oregon State just 120 yards on the ground, but the Beavers' running game has been dismal this season with an average of just 68 yards a game.
The Buffaloes rank ninth in the league for overall defense, allowing 391.7 yards a game.
Last year, Oregon defeated Colorado 70-15, rolling to 617 yards in total offense, including 425 yards on the ground in Eugene.