CORVALLIS - Minor adjustments to the Oregon State football team's roster were necessary due to injury and academic issues, coach Mike Riley said Wednesday.

Redshirt freshman defensive tackle Jesse Fifita's playing career is over due to spinal stenosis, which is the narrowing of the spinal cord that causes nerve pinching. It leads to persistent pain in the buttocks, limping and lack of feeling in the lower extremities.

The condition is most commonly caused by osteoarthritis-related bone damage, according to the Mayo Clinic.

Fifita suffered repeated stingers during spring practice. When he got them in both shoulders at the same time they had him checked out.

"Jesse was a great prospect coming off a redshirt year," Riley said. "He had both shoulders at the same time, which immediately throws up a red flag."

There were three opinions on his condition, and they all agreed he should not play football anymore. He's listed as a medical redshirt, which means he stays on the team on scholarship.

Fifita was expected to be part of the defensive line rotation this season. He is a 6-foot-1, 285-pounder who moves well.

"It was one of the worst (experiences) to sit in there and tell him he should not play," Riley said. "He wanted to get more opinions, but frankly I told him that when one neural surgeon says this and we pass it on to two more - one in the NFL and another one who handles a college team - and they say the exact same thing, there's no way I would let him on the field. It was not fun. This kid has worked hard and surprised everybody."

Incoming linebacker recruit Michael Doctor will greyshirt due to academics. He would have probably redshirted this season.

"It was very disappointing; it was a surprise two weeks ago," Riley said. "But he'll be here in January."