Brooks' family released a statement Wednesday updating his status, which was confirmed by an LSU official.
The Arkansas transfer missed last weekend's win at Mississippi State for undisclosed reasons. Coach Brian Kelly had called it a "medical emergency" on Monday but said he did not want to go into details out of respect for the Brooks family. Kelly said he did not have a timeline for Brooks' return.
According to the statement, the surgery to remove the "large brain tumor" was successful and the family is awaiting results of a biopsy.
"We are grateful for the work and care of the medical staff helping Greg through these challenges and for the concern and love poured out by so many in the Louisiana, Arkansas and national sports communities," the family said. "This means the world to us at this difficult time.
"Greg continues to fight, and we await further clarity on the extent of that battle."
On Wednesday's SEC teleconference, Kelly said Brooks' bout with vertigo earlier in the year ended up being a symptom of the tumor. Kelly said Brooks felt dizziness again this past Wednesday and they decided to perform an MRI, which revealed the tumor.
Asked whether he anticipated Brooks playing again this season, Kelly said he did not know but added that, when he saw Brooks before the surgery, the fifth-year senior had his mind made up.
"He was pretty clear about playing again this year," Kelly said. "But that's Greg Brooks."
A Louisiana native who went to West Jefferson High School, Brooks transferred to LSU prior to last season. He started all 14 games in 2022 and was fifth on the team in tackles with 66.