Gordon Hayward’s awful injury ended his first Celtics season before it started

Three-hundred and fifteen seconds.

That’s how much time came off the clock in the first game of the NBA season before Gordon Hayward gruesomely dislocated his left ankle, potentially ending his long-awaited first year in Boston before it ever started.

We won’t publish the video, so I’ll tell you what happened: Hayward went up after a lob pass and clipped LeBron James, who was defending it. James is listed at 250 pounds but looks and probably feels much stronger; after a year-plus of bulking up, Hayward is listed at 209.

The outcome was a loud thump, followed by a showering of murmurs from the crowd that sucked the air out of Quicken Loans Arena. If you didn’t know what happened, play-by-play commentator Marv Albert made it clear:

Hayward was a Celtic well before he signed a four-year, $128 million max contract this summer.

Jazz fans hoped he would re-sign long-term in Utah after leading them to their best season in the post-Jerry Sloan era. But for most outside of Salt Lake City, Hayward’s mind was already made, and why wouldn’t it be?

He was going to go to Boston, where he’d rekindle a relationship with his college head coach Brad Stevens. He was going to Boston, where he’d play next to Isaiah Thomas — eventually, Kyrie Irving — and Al Horford. And he was going to Boston, a legendary franchise that afforded him an opportunity to pursue the coveted NBA championship he couldn’t sniff in the stacked Western Conference, no matter how good the Jazz were.

At a moment’s notice, that all came crashing down.

There’s no word on how long Hayward is out for, but if you saw the injury, you’ll probably agree it’s a safe bet he’s done for the year.

The Celtics aren’t empty on the wings. Jaylen Brown is projected to have a breakout second season. Boston traded for Marcus Morris, a tough-nosed versatile forward, and drafted Jayson Tatum — an elite wing scorer — No. 3 overall in June’s NBA draft. Those three will have to pick up the slack by committee.

But Hayward was supposed to be the star at the wing that legitimized the Celtics’ odds at competing with Cleveland. And after all the buzz his arrival in Boston created, it’s just unfortunate his first season with the Celtics ended before it ever had a chance to take flight.