Brown’s TDs were both more than 50 yards long, and he averaged 12.36 yards per carry.

“Right now, the way we’re running, that doesn’t look like it’s possible,” Colorado coach Gary Barnett said of today’s 2:30 p.m. game against Kansas (4-1 overall, 1-0 Big 12 Conference) at Folsom Field in Boulder, Colo.

Brown left school after his junior season, and senior tailback Bobby Purify was expected to miss his third straight game today because of an ankle injury.

The Buffs (2-3, 0-1) are averaging just 2.26 yards per carry and have been held to less than 100 yards rushing in four straight games. Their 85.4 rushing yards per game ranks 112th among 117 Division I-A teams.

It’s not what was expected from the two-time defending Big 12 North champion.

“Colorado’s still a very good football team, and we’d be fools to count them out in any way right now,” KU coach Mark Mangino said.

CU went 2-2 against a rigorous nonconference schedule, defeating Colorado State and UCLA before suffering back-to-back losses to Washington State and Florida State.

After a bye week, the skid reached three games last Saturday at Waco, Texas, with a 42-30 loss to Baylor.

“Five turnovers and 26 missed tackles was the difference in the game,” Barnett said. “In a nutshell, that’s what the game boiled down to. We had a couple of guys play well, but obviously not enough. Right now the fundamentals of blocking and tackling are not where it needs to be for us to win those kinds of games.”

The Buffs have been outscored 136-63 in their last three games. So what does Mangino have to fear?

Colorado ranks 15th in the nation in passing offense with an average of 299.6 yards per game — glossy numbers for a team using two sophomore walk-ons at quarterback.

Joel Klatt started the first three games before suffering a shoulder injury in a 47-26 loss to Washington State. Backup Erik Greenberg started the next two games, but he was replaced by Klatt late in the Baylor game after suffering a hand injury.

Both quarterbacks were expected to be ready for today’s game.

Their numbers are similar. Klatt (6-foot-1, 195 pounds) has completed 59.8 percent of his passes for 728 yards and six TDs with one interception, while Greenberg (6-2, 200) has completed 55.1 percent of his passes for 710 yards and six TDs with three interceptions.

Neither quarterback presents a threat on the ground. Greenberg has rushed for minus-27 yards, while Klatt has lost 33.

Mangino said Kansas would be prepared for both quarterbacks.

“We think those guys are pretty close in talent and ability,” he said. “I don’t see a big difference in them. I really don’t. They both competed for that position, and Klatt got the nod. Greenberg is an impressive guy who makes plays. They put up around 450 yards of offense on Baylor. Either quarterback is capable.”

CU’s big-play threats are senior receivers Derek McCoy (6-3, 205) and D.J. Hackett (6-3, 200).

Hackett leads the team with 33 receptions for 420 yards and a touchdown and tops the Big 12 with an average of 6.6 receptions per game. McCoy has 29 receptions and leads CU with 554 yards and six TDs. His 110.8 receiving yards per game leads the league.

KU limited highly-touted Missouri quarterback Brad Smith to 62 passing yards in a 35-14 victory Sept. 27 before having a bye week to get ready for CU.

“Our last opponent had some good receivers, and I felt that we matched up pretty well,” Mangino said. “This will just be another challenge for them. Our kids are getting better in the secondary. They are playing with more confidence. You can see them on the practice field; they have a little swagger to them that was missing in the past.”

Colorado has been hampered by injuries and inexperience on defense and ranks 112th in scoring defense and 114th in pass defense.

Senior cornerback Phil Jackson called the team “a disgrace” to CU’s former players, and the Buffs had a players-only meeting Sunday after the Baylor loss.

“We’ll see how it goes, but we needed to have it,” senior center and team captain Marwan Hage said. “It is a minor setback for us right now. We still have seven or eight games left. We won’t let one game wreck our season.”

The Buffs — who play a tough nonconference schedule every year — have stumbled out of the gate before. In 2000, CU opened with losses to Colorado State, Southern Cal and Washington, never recovered and finished 3-8. In 2002, CU lost two of its first three before winning eight of its last nine and repeating as Big 12 North champs.

Today’s game could be Colorado’s chance to turn things around before running the gauntlet of Kansas State, Oklahoma and Texas Tech in the next three weeks.

“It’s tough to win in Boulder,” said KU linebacker Banks Floodman. “I don’t care what their record is. They’re going to … fight and claw, but we’re going to fight and claw, too.”