Six minutes into the Celtics’ season premiere Tuesday night, Gordon Hayward dislocated his ankle and broke his tibia. He will undergo surgery soon, and we should know more about a potential recovery within days. It’s likely to be quite bad news for Boston.

The NBA season is unforgiving, though. The Celtics had to finish the game against the three-time defending Eastern Conference champion Cavaliers on Tuesday, and they have another match on Wednesday. Injuries occur and the season marches on. There’s no time to recover mentally or strategically.

So what do the Celtics do now? This team had grand designs on repeating as No. 1 seed, winning another Atlantic Division banner, making the NBA Finals, maybe even challenging the hegemonic Warriors. Is all that shattered in one fall six minutes into the season?

Perhaps not.

Related Celtics face challenge of regrouping after the loss of Gordon Hayward

Marcus Smart is ready

Hayward’s absence will likely push Marcus Smart into the starting five permanently alongside Kyrie Irving and Jaylen Brown on the wings. Smart has looked great in both the preseason and in Tuesday’s opener, despite shooting 0 for 4 from deep in Game 1.

Marcus bullies his way to the bucket pic.twitter.com/SL1My2zz9R — Boston Celtics (@celtics) October 18, 2017

The toughness he brings and his defensive versatility should mean there is limited drop-off from Hayward on that end of the floor. With Brown remaining in the starting five, there is strong wing defense for the Celtics.

Smart isn’t nearly the shot creator, shooter, or scorer that Hayward is — few are, to be honest. That’s why landing Hayward was such a coup in July! But Smart is a good young player who is in great shape and should plug nicely into the starting five. He’s started 72 games over three years as Brad Stevens accounted for injuries and mixed up his rotations; he’ll likely get at least 72 more starts this season alone, barring injury.

Jayson Tatum is real

To help cover the offensive loss of Hayward, much will be asked of Jayson Tatum. The good news is that Tatum had an excellent debut with 14 points, 10 rebounds, three assists, and just one turnover.

Irving ➡️ Tatum. He's got 14pts and counting in his rookie debut. pic.twitter.com/f4kkBGWOR4 — Boston Celtics (@celtics) October 18, 2017

The Celtics’ Danny Ainge traded down from No. 1 because he believed Tatum was the best prospect in the 2017 NBA draft. If he’s right and Tatum shows out, that’s a nice saving grace for Boston in a difficult moment. While it would have been nice to see Tatum thrive alongside Hayward, the scoring punch he can offer without the co-star will be much appreciated.

We’ll see whether Stevens chooses to keep Tatum as a starter once Marcus Morris is healthy or shifts him to the bench to provide scoring punch there. Either way, having a rookie who is actually productive is quite a luxury.

Jaylen Brown isn’t afraid

Brown was the Celtics’ leading scorer on Tuesday, scoring 25 points on 24 shooting possessions. He also had no assists and three turnovers. Altogether, it wasn’t a terribly efficient night for the young Brown.

But the volume is interesting. As a rookie last season, Brown never took more than 16 field goal attempts in a game. He had 23 (plus a pair of free throws) on Tuesday. He stepped up. The quality of the shots needs to improve, and he has a lot to learn about moving the ball to open teammates. But for a defense-first athlete whose offense has been considered a work in progress, the aggressiveness he showed Tuesday was downright refreshing.

If the Celtics coaching staff can help him find his spots better, and he can learn how to play off Kyrie, Brown could make a real difference in Hayward’s absence.

The Celtics’ window is wide open

Perhaps the most important item to remember in considering the Celtics’ future without Hayward is that the horizon is vast. Hayward may miss the entirety of 2017-18, playoffs included.

But he signed a four-year deal with the Celtics, and he’s only 27 years old. Irving is 25. Brown only about to turn 21, and Tatum is a teenager. Al Horford is the team’s resident old man, but he’s just 31 with relatively low mileage thanks to a long college career and a few injury-shortened seasons.

If Hayward can’t play a meaningful NBA game until next October, all is not lost for the Celtics’ huge victory in landing him. There is always next year. That’s the beauty of Boston’s construction: The Celtics are built to win right now, and also tomorrow, and also next year, and also three years from now. There is time.

This brutal injury hurts Hayward physically and Boston psychologically. But the sun will rise on the Celtics again, and soon.

Gordon Hayward's injury met by outpouring of support