Lady Bears head coach Kim Mulkey said in a statement issued late Thursday that Griner will be suspended for one game in addition to a one-game suspension mandated by NCAA rules.
Griner was automatically suspended for Baylor's next contest, Sunday's match-up against No. 18 Texas in Waco. Mulkey's additional one-game suspension will force Griner to miss Baylor's Big 12 Championship tournament opener on March 11 or 12.
"Due to the severity of the act, it is appropriate that Ms. Griner is suspended for an additional game," said Big 12 commissioner Dan Beebe in a statement. "Therefore, I have accepted Baylor's action and commend athletics director Ian McCaw and head coach Kim Mulkey for taking a strong stance to support good sportsmanship."
The Big 12 tournament is next week in Kansas City, Mo., and Baylor is all but guaranteed a spot in the NCAA tournament the following week.
In the written statement from Baylor, Griner apologized to "the Lady Raider team, my teammates and coaches, the fans and the game of women's basketball."
"I let my emotions get the best of me and I am deeply sorry for my actions. I am committed to doing a better job of maintaining my composure in the future," she said. "I will grow from this and I am dedicated to setting an example to others of how to learn from personal mistakes."
The 19-year-old Griner is one of the most talked-about women's college players in years. The Houston native was an Internet sensation in high school with her incredible dunks and earlier this season she became only the second player to dunk more than once in a women's college game during a 99-18 rout of Texas State. Candace Parker of Tennessee was the first.
She was tentative at first, but has become one of the most dominant frontcourt players in the country and gets the most attention from opposing teams. On Wednesday night, she punched Texas Tech's Jordan Barncastle in the face after the two players tangled in the second half of Baylor's 69-60 win in Lubbock.
The 6-foot-8 Griner and Barncastle were battling for position near the lane before Barncastle spun around and sent Griner lunging toward the baseline. As a foul was called on Barncastle, Griner straightened up and took two steps toward her before throwing a roundhouse punch with her right hand.
Players had to be separated in the scrum that ensued, and Baylor's Morghan Medlock was given a technical foul.
Barncastle stayed in long enough to shoot four technical free throws but didn't play again. Video showed her on the bench with gauze in her right nostril, smiling while describing the play to teammates by simulating a punch.
Barncastle's father and former high school coach, Doug Barncastle, said his daughter's nose was broken and declined further comment. Texas Tech spokeswoman Tammi Hoffman said Barncastle would be evaluated daily and it wasn't clear when she would be cleared to play.
After the game, Mulkey said she would deal with Griner but didn't plan to discuss disciplinary measures publicly.
"There's no place for that in sports," Mulkey said. "It was ugly for women's basketball."
Griner towers over opposing players forced to be physical with her around the basket.
Griner is averaging 19 points, 8.7 rebounds and 6.1 blocks -- second nationally -- per game. She has season highs of 34 points and 21 rebounds, while recording 11 blocks in three different games. She already holds the Big 12 single-season blocks record.