One day after we learned that former Boston Celtics forward RJ Luis would be able to go back to college and play for LSU, it looks like he won't be allowed after all.

As noted by Jon Rothstein of CBS Sports, the Southeastern Conference (SEC) has passed a rule that says any players who signed professional contracts will be ineligible to return to college basketball.

It's a complex topic, so let's take it step-by-step.

Luis, a 6-foot-7 forward from Miami, Fla. spent three years in college. A member of the high school graduating class of 2022, Luis played his first year at Massachusetts and then two years at St. John's. For his career, he averaged 14.1 ppg, but he averaged 18.2 at St. John's in his junior year under Rick Pitino. He was a major part of St. John's resurgence under the former C's head coach.

He did not play with current Celtics forward Dillon Mitchell, who the Celtics took in the second round this year out of St. John's.

Luis was named the Big East East Player of the Year in 2024-25, but went undrafted in the 2025 draft.

Luis signed with the Utah Jazz last summer and then was dealt to Boston before being waived in October of 2025. He then signed on with the Maine Red Claws, the G-League affiliate of the Celtics. He signed an Exhibit 10 contract in this case, which is important to note.

He did not play any games in Maine. He did play in the Celtics preseason. He scored six total points.

The NCAA adopted a new rule this summer that gives athletes five years to play as many seasons as they can, with a few exceptions.

As a result, there are no more redshirt years and no more medical redshirts. If a player sits out a year, for any reason, they will just have four years of eligibility as they did previously. If they miss two years because of injuries in that five-year span, they'll end up with just three seasons played.

In Luis's case, he came in with the high school Class of 2022. He played three seasons in three years, and his fourth year was spent trying to be a professional.

However, he was given an injunction that was going to allow him to go back to school, essentially saying that the 2025-26 year was just a year off and he deserved that fifth year, and fourth year of eligibility. 

More chances to show off for NBA scouts. Another chance to get drafted. More NIL money. All would be relevant reasons.

Because Luis had an Exhibit 10 contract with the Celtics, that means he signed a professional deal, and the SEC is banning those kind of players from returning to school. 

Players who play only in Summer League could still be eligible, given that a Summer League contract is not the same as a standard NBA contract. 

But that isn't Luis, so he'll have to stick in the professional ranks.

While Luis can challenge the decision in the court, SEC programs, like LSU, won't be able to take him without significant penalties, and it probably isn't worth it to those schools to absorb those penalties.