•Stuck in limbo, OSU’s Larry Williams participates in Pro Day while awaiting NCAA ruling.

— For one of two reasons, April 28 will be an important day for Larry Williams.

He just doesn’t know which of the two will make it important.

There’s a chance he’ll be watching the final day of the NFL Draft, either hoping to hear his name called, or waiting for a phone call offering an undrafted free agent opportunity.

Or there’s a chance he could be playing in Oklahoma State’s annual spring game at Boone Pickens Stadium.

The oddity is that Williams doesn’t know which he’ll be doing. That’s why the 6-foot-4, 327-pound offensive guard was a full participant in Oklahoma State’s Pro Day, which drew scouts and frontoffice people from all 32 NFL franchises — some sending multiple representatives.

Yet Williams will be with the Cowboys, though likely not participating, when spring practice opens on March 27 as he awaits the NCAA’s final ruling on his appeal for a sixth year of eligibility in a situation so unique it might never occur again.

“I’m in a little gray area,” Williams said. “Am I leaving? Am I coming back? I’m really just waiting on (the NCAA). I’m gonna just keep working until then.”

Williams suffered a broken ankle during practice prior to OSU’s game against TCU last season, ending his year after only three games. The year before, an injury limited his season to just five games.

Oklahoma State entered into the process of seeking a sixth year of eligibility for Williams last fall.

He won’t know until April 18 whether or not he will receive the extra season, which leaves him in limbo as spring practice and the NFL Draft loom.

Williams received special permission from the NCAA to take part in typical pre-draft activities like Pro Day without affecting his eligibility. He still can’t sign with an agent or do anything else that would impact his amateur status.

The reason Williams doesn’t yet know his fate is because of a potential NCAA rule change that will be voted on a month from now.

Currently, to receive a sixth year of eligibility for medical reasons, an athlete must miss 70 percent or more of a season twice during his career.

The proposed change would alter the rule to require that at athlete miss 70 percent of only one season, not including a redshirt season, to be eligible for a sixth year.

Williams’ initial appeal was denied, because while he had missed more than 75 percent of the 2017 season, he hadn’t reached that mark in 2016, playing five of OSU’s 13 games, including a few snaps in mop-up time of the team’s Alamo Bowl win. Playing in a game beyond the midpoint of the season also nullifies a medical hardship appeal.

From what Williams has been told, there’s a better-than-average chance that the rule change will be approved next month, and he’ll be granted his additional year. He says he’s almost certain he would remain at OSU for the 2018 season.

“If I get the year, I want to come back, but if someone gives me a shot at the NFL, like on a practice team or anything like that, I think I’ll just move on,” he said. “It really just depends on where the cards lay an how things turn out this next month.”

Until the NCAA makes its ruling, Cowboy coaches have decided to keep Williams on their regular training plan, but will hold him out of practice when it begins later this month to prevent damaging his NFL stock with another injury.

Assuming he gets the extra year, Williams is almost certain he would return — unless an NFL team starts talking to him

If Williams doesn’t get his extra year, he’ll turn his focus fully to the NFL. And Thursday was a good start, with what he believed was a strong workout despite not being back to full health.

“I’m obviously not 100 percent,” he said. “I’m like, 85, 90 right now. I’m still progressing to get my ankle fully healthy. But I feel like things went good today.”