It's unlikely Colorado will have its leading rusher when it travels to UCLA this week.

True freshman Michael Adkins II hasn't practiced as he continues to recover from a concussion suffered in last week's loss to Arizona. Adkins' absence means senior Tony Jones and sophomore Donta Abron are likely to see more playing time behind Christian Powell, who has started six of the first seven games.

"I feel confident about those guys," CU running backs and tight ends coach Klayton Adams said. "There are a couple of guys who are getting an opportunity who have haven't had opportunities the last couple weeks. ... I have total faith in those guys. They've worked really hard, they've stayed really focused in the weeks they didn't play as much."

Jones and Abron have played in all seven games on offense this season but neither has had a lot of success. They have combined for 55 carries for 205 yards no touchdowns. Jones is responsible for the bulk of that production having rushed 44 times for 183 yards.

Jones was the backup to Rodney Stewart in 2011 and began the 2012 season as the starter, but he was eventually surpassed by Powell, who put together one of the best seasons by a freshman running back in school history last fall.

Jones has been forced to deal with a diminishing role again this season with the emergence of Adkins in the Oregon State game back in September. Powell and Abron, who appeared to be blossoming late last season, also have taken a back seat to Adkins at times.

"It's my time to fill in the spot," Jones said. "You know you play different roles. That's why we practice so hard and that's why everybody gets reps because you never know what happens. If an injury comes, the next person in should be the same as the person that they're in for."

It's easy to see why Adkins has taken a more prominent role, even though Powell has remained the starter in three of the past four games. Adkins is averaging nearly six yards per carry. None of the other backs on the roster is averaging more than four yards.

The Buffs have been making small improvements in the running game with the combination of Adkins and Powell handling most of the workload, but they're still gaining just 128 yards a game on the ground.

If the Buffs hope to pull off an upset over No. 17 UCLA on Saturday, big days would likely be required of Powell, Jones and Abron.

"We just got to play together as a team, stay focused and listen to the coaches and believe in what they've coached us up to this point, and then just go out and make things happen," Abron said.

It's a homecoming of sorts for Powell and Abron, who were high school teammates in Upland, Calif., just east of Los Angeles.

"It's always exciting to get on the field and try to make something happen for the team," Abron said. "So, yeah, it will be great, especially in front of my family."