EUGENE, Ore. -- Oregon tailback Onterrio Smith hopes his left knee has healed enough for him to play in Saturday's game at Washington State.

Smith missed last week's game against Stanford but has returned to practice for the 15th-ranked Ducks (7-2, 3-2 Pac-10), who will play their most important game of the season against the fifth-ranked and conference-leading Cougars (8-1, 5-0), the conference leader.

Smith, who leads the Pac-10 with an average of 126.88 yards a game and 12 rushing touchdowns, injured the knee sometime during the first half of Oregon's 44-33 loss to Southern California two weeks ago.

Smith was held to 79 yards rushing by the Trojans, stopping his streak of seven straight games with at least 100 yards.

He said the Washington State game Saturday is too important to miss.

"We know this game has a big effect on the season,'' he said. "If we win it, it could turn our season around.''

Smith ran for a school-record 285 yards and three touchdowns against the Cougars last season, including a 73-yard TD in the fourth quarter that provided the winning margin in the 24-17 victory. And he was playing backup to Maurice Morris.

The Ducks didn't need Smith in their 41-14 victory over the Cardinal last Saturday. They had freshman Terrance Whitehead, who rushed for 132 yards in his first start.