(Photo credit: Ron Chenoy-Imagn Images)

Oklahoma State and Colorado entered the conference schedule with momentum then struggled once Big 12 play began.

Both are seeking a boost when the Cowboys visit the Buffaloes on Saturday afternoon in Boulder, Colo.

Oklahoma State (16-10, 4-9) has lost four in a row, the last against No. 8 Kansas on Wednesday night, and its 12-1 start to this season has quickly faded in the loaded Big 12.

Things just got tougher for the Cowboys, who announced Thursday that big man Lefteris Mantzoukas has left the program for health reasons.

'Lefty has been a tremendous teammate and person during his time in Stillwater and will be deeply missed,' Oklahoma State coach Steve Lutz said in a statement.

Mantzoukas was a key role player for the Cowboys, averaging 4.4 points, 4.2 rebounds and 17.8 minutes in 12 games. Oklahoma State is led by Anthony Roy, who is averaging 17.5 points, while Parsa Fallah (14.5) and Vyctorius Miller (12.0) are also scoring in double figures.

Colorado (14-12, 4-9) is coming off a tough overtime loss at No. 23 BYU a week ago and has a chance to stack up two home wins before facing two of the top four teams in the nation -- No. 2 Houston and No. 4 Arizona -- in its final three games.

Despite the Buffaloes' struggles, there are positives to this season. Their leading scorer is freshman Isaiah Johnson, who had a career-high 27 points in the loss to the Cougars on Feb. 14. He is averaging 16.5 points a game and has earned the respect of his head coach.

'Isaiah Johnson is the best freshman in the country that nobody talks about,' Colorado head coach Tad Boyle said after the loss to BYU. 'I believe he'll be an NBA player someday.'

Sebastian Rancik, another freshman, is third in scoring for Colorado at 12.5 points. Barrington Hargress leads the Buffaloes in assists (4.3) and is second in scoring at 14.1 points.

--Field Level Media