Tailback Silas Redd hopes to make his season debut on Saturday for No. 25 Southern California after getting more repairs done on his left knee last week.Redd didn't practice with the Trojans on Tuesday night, watching from the sideline in his jersey while wearing a brace on his knee. The Penn State transfer is still optimistic he could play against Washington State at the Coliseum."It's nothing I asked for," Redd said of the injury that has slowed his senior season. "But it is what it is, and I'm taking it as positively as I can."Redd missed most of spring ball and training camp after tearing his meniscus early in spring practice. Nearly six months after the initial surgery, he's still waiting to get back to full strength.While USC beat Hawaii 30-13 last Thursday in its opener, Redd watched the game from Pensacola, Fla., after undergoing what he described as a "minor" procedure on his knee by Dr. James Andrews. Redd is forbidden from giving more details about his condition, but he's maintaining optimism about getting back in the near future."I'm just glad he had the time to see me," Redd said of Andrews.Redd led the Trojans last season with 905 yards rushing and nine TDs after transferring shortly before training camp. He quickly fit in with a new offense and new teammates, but was slowed by injuries down the stretch of the Trojans' disappointing 7-6 season.He is expected to be USC's starting tailback again this season, but has been reduced to a mentor's role so far. He must be doing a good job: USC looks deep at tailback after just one game in which the Trojans ran the ball 45 times."I was extremely proud," Redd said. "We almost had two 100-yard rushers out there."Sophomore Tre Madden rushed for 109 yards against Hawaii in the converted linebacker's first game at tailback. He missed all of last season and last spring's practices with a knee injury.Madden was nearly upstaged by 17-year-old Justin Davis, who added 74 yards and a rushing TD in his first collegiate game while displaying a smooth, confident running style. Davis fumbled, but otherwise looked ready for a role with the Trojans."There were a lot of good things, led by Justin Davis," coach Lane Kiffin said. "If he doesn't fumble that ball, he was going to have a 100-yard day in his first game. I think Reggie (Bush) had about 9 yards in his first game. So it's not an easy thing to do, and he did a really good job in there, and now he's got one under his belt, and he's going to continue."With tailback D.J. Morgan also sidelined by injuries last week, Javorius "Buck" Allen was the only tailback available who had carried the ball in a game before. Allen rushed for 18 yards against Hawaii."(Davis) had a little adversity out there with the fumble, but he bounced back and scored that touchdown," Redd said. "Buck Allen had some great blocks, and Tre had a great game. I just tell them that you don't get these opportunities all the time. Playing running back at USC is a big thing."