NEW ORLEANS -- Boston Celtics head coach Brad Stevens detailed Sunday what happened with Gordon Hayward's injury setback a month and a half ago.

According to Stevens, the issue was a "small" one that should not impact Hayward long term. Hayward, who has been building toward running on his own, developed some soreness while trying to push himself on the AlterG anti-gravity treadmill. The Celtics All-Star needed to dial it back for a couple of weeks before advancing back to more strenuous work.

"It was just a typical, we're doing a progression and he had some soreness out of that progression," Stevens said Sunday before a meeting with the New Orleans Pelicans. "So we talk about, like, moving on in the AlterG - running (with) 50 percent of your body weight to 60, 70. Stuck at 50, take a couple steps back for a couple of weeks and then resume."

Stevens said the setback, revealed recently on the radio by Celtics president of basketball operations Danny Ainge, was "probably a little bit predictable based on how (Hayward has) been working and everything else."

"There's going to be some soreness," Stevens said, "and I think you're weighing and measuring that too. But yeah, then that's why he resumed the AlterG activity a couple weeks later. But nothing that would be a long-term issue or anything like that. Small."

Shortly after Hayward's setback, the Celtics started changing their message about the All-Star's chances of returning this season. Stevens ruled out any possibility, but Hayward later said he still has hopes of playing again in 2017-18.