LOS ANGELES (AP) -- UCLA running back Steven Manfro left the practice field on a cart Tuesday after apparently injuring his knee.
''Everyone was pretty shook up,'' UCLA coach Jim Mora said. ''It kind of changed the mood of the entire practice. ... It upset everybody when a guy who is as critical as Steven gets hurt. I don't know if it's serious or not. Sometimes they don't end up being as serious as they looked, but that looked pretty serious to me.''
Manfro had two carries for minus-5 yards as the Bruins' running game struggled in their season opener at Virginia. The junior also returned kickoffs last season.
Freshman Nate Starks is likely to assume an increased role if Manfro's injury is significant, but the Bruins have plenty of work to do in their running game no matter who ends up carrying the ball. Manfro is a versatile back and a passing target, although he dropped two passes at Virginia.
UCLA fell four spots in the AP Top 25 after its 28-20 victory over Virginia last weekend. The Bruins (1-0) host Memphis at the Rose Bowl on Saturday night.
The Bruins' offense was hampered in Charlottesville by poor play on the offensive line and in the running game, which managed just 78 yards and no touchdowns from that three-tailback group.
Brett Hundley also struggled at times behind the line, which is missing two key injured players: three-year starting center Jake Brendel and Simon Goines, who started six games at left tackle last season.
While the Bruins hope Brendel is close to returning from his knee injury, offensive line coach Adrian Klemm doesn't excuse his unit's performance with Brendel's absence.
Klemm said the line's effort was ''probably one of the (worst) performances I've been a part of as a player or a coach.''
''I knew we would struggle a little bit, but you don't expect it to that degree,'' added Klemm, a three-time Super Bowl champion with the New England Patriots. ''Things that we haven't done before in practice got us off track, and it was very hard to get back.''
Guard Scott Quessenberry filled in at center for Brendel, but acknowledged he struggled at times. So did freshman guard NaJee Toran and left tackle Malcolm Bunche, whose inability to pick up Virginia's pass rushers was glaring.
The Bruins' potentially powerful offense will have trouble lighting up scoreboards without solid line play, but Klemm is confident his group will improve, hopefully before the Pac-12 schedule begins.
''If they're not talking about us, it's a good thing,'' Klemm said. ''And people are talking about us way too much right now.''