Griffin was one of the highest rated and most decorated recruits ever at Oklahoma. As a freshman at Oklahoma, he averaged 14.7 points and 9.1 rebounds and led the Sooners to a 23–12 record. He ranked ninth in scoring, fourth in rebounding and third in field goal percentage in the Big 12 Conference. In a game against the Kansas Jayhawks, he suffered a sprained medial collateral ligament (MCL) in his left knee five minutes into the game. Less than two months after injuring his left knee, he injured his right knee in a home victory against Texas A&amp;M. The injury this time was torn cartilage, and he had arthroscopic surgery on March 2, 2008. He missed the following game, a victory over in-state rival Oklahoma State Cowboys, but was back on the court a week after the injury with 14 points and eight rebounds in a win versus Missouri. Griffin was a first-team all-district pick by the USBWA and NABC, and was named to the Big 12 All-Rookie Team and to the first-team All-Big 12 selection by league coaches and Associated Press. He became the first Sooner to make the conference All-Rookie team since Wayman Tisdale in 1983 for the Big Eight Conference. He was expected to be a lottery pick in the 2008 NBA draft but decided to return to college to give himself time to mature physically and try to help Oklahoma win the NCAA championship.