STANFORD, Calif. -- Colorado wide receiver Paul Richardson is expected to miss three more games before he will be healthy enough to return from a sprained knee suffered last week in practice, coach Jon Embree said.

Richardson traveled with the team to watch CU play at Stanford on Saturday where the Buffs were battered 48-7 by the seventh-ranked Cardinal. Embree said the CU offense missed its biggest threat to defenses.

Redshirt freshman Keenan Canty started in Richardson's place and senior Logan Gray also was more involved in the offense. Those two players caught three passes each, but neither has the speed or leaping ability that make Richardson special.

"We're really thin at the receiver spot," Gray said. "So me and some of the other guys are going to have to step up and try to make some plays on offense."

Richardson is the Buffs' leading receiver with 29 catches for 474 yards and five touchdowns this fall. He is averaging 16.3 yards per catch. He is the second CU receiver injured in the past week. Senior wideout Kyle Cefalo injured his elbow against Washington State last week and also did not play.

Trust issues

It's hard to blame CU freshman place-kicker Will Oliver for feeling a little gun-shy. His teammates have allowed blocked field goals in each of the past two games.

After having his first-quarter field goal blocked by Stanford linebacker Max Bergen on Saturday, Oliver admitted he was a little distracted on his next attempt and he missed the 46-yard attempt wide left.

"That second one was a little on me, I didn't really trust the line that much," Oliver said.

The blocks against Washington State and Stanford have involved a defender coming through the middle of the line. Embree replaced the player who allowed it to happen the first time and it happened on the opposite side on Saturday.

Peek at the future?

It was more of a bit part than a supporting role, but CU backup quarterback Nick Hirschman will take it.

Hirschman played for the first time in his college career in mop-up duty Saturday. He completed the only pass he threw to Tyler McCulloch for a two-yard gain, but he was happy to at least have the initial exposure to the speed of a college game under his belt.

"It was just really exciting to go in there and play in my first college game," he said. "Any experience is good experience."

More on suspensions

Embree was asked after the game how long the five defensive players he suspended would remain out of action. He suspended Ayodeji Olatoye, Liloa Nobriga, Parker Orms, Paul Vigo and Josh Moten indefinitely earlier in the week for team rules violations.

"It's going to be awhile," Embree said. "As bad as this feeling is right now sitting here, I'm not going to compromise the rest of those guys in the locker room or the integrity of this program."

Speedy provides spark

Colorado's kickoff return team has been ranked dead last in the Football Bowl Subdivision for much of the season, but tailback Rodney Stewart has added a different element to the unit of late. And unfortunately the Buffs got a lot more practice Saturday.

CU averaged 24 yards per return against Stanford or eight more yards than it had averaged in the first five games.

The Buffs also helped themselves on kickoff coverage, where they also rank last in the nation. They were allowing 29 yards per return before Saturday. Stanford averaged 12 yards on its two returns.

Day of firsts

Linebacker Woodson Greer became the 13th true freshman to play for the Buffs this year seeing action on special teams. Defensive back Terrel Smith made the first start of his career at cornerback. He had previously started as a safety. He also made the second interception of his career in the second quarter.

Running back Tony Jones scored the first touchdown of his career and Canty made the first start and catch of his career. True freshman offensive lineman Paulay Asiata and redshirt freshman Kaiwi Crabb both saw the first action from scrimmage of their careers.

Tailback Josh Ford and linebacker K.T. Tu'umalo also saw their first action on offense and defense, respectively. And defensive linemen Kirk Poston and Eric Richter and wide receiver Alex Turbow played for the first time at CU.

Sack streak ends

The Buffs had registered at least one sack in 11 straight games and 36 of their last 37 prior to Saturday. They did not manage to drop a Stanford quarterback, which continued Stanford's strong track record of protection this fall. The Cardinal has allowed just two sacks in five games.

Notable

Colorado committed a season low of six penalties for 47 yards. ... Sophomore linebacker Derrick Webb and Canty changed jersey numbers when both were added to special teams units where teammates with duplicate numbers were already participating. Webb now wears No. 1 and Canty wears No. 84. ... CU sold out its allotment of 2,700 tickets for Saturday's game and has sold 1,300 tickets for next week's game at Washington.