When the 2017 NBA offseason got underway, the Boston Celtics picked up former Utah Jazz superstar Gordon Hayward and it looked like they were ready to step up and compete head-to-head with the Cleveland Cavaliers. Things did not go as planned on opening night when Hayward and his Celtics took on the Cavaliers. Just five minutes into the game, Hayward broke his ankle in one of the most gruesome injuries the NBA has seen in a long time.

However, it isn't the first time a superstar fell to a horrific injury. Here is a look at 5 of the most gruesome injuries in NBA history.

Shaun Livingston's knee injury

A very similar injury happened to Shaun Livingston back in 2007. He was driving down the court after stealing the ball and went up for a layup but came down awkwardly. Instead of breaking his ankle, it was his knee that bent the wrong way. At the time, Livingston was a hugely promising star but this was one of the most gruesome injuries in NBA history and his career was never the same.

Marquis Daniels is knocked out

Not all gruesome NBA injuries involve a body part breaking in a horrific manner. In the cast of Boston Celtics star Marquis Daniels, it was scarier. Daniels was moving towards the basket with the ball and tried to go around Gilbert Arenas. As Daniels tried to move around him, his neck snapped and he just dropped motionless to the ground.

He didn't move again for five minutes and was stretchered out. The diagnosis was a bruised spine.

Andrew Bogut dislocates his elbow

A more recent injury came in 2010 when the Phoenix Suns and Milwaukee Bucks were playing when Andrew Bogut was driving in for a big dunk over the Suns. Bogut got tangled up in the net when he dunked the ball, his body twisted in midair and he came down hard, dislocating his elbow, breaking his hand, and spraining his wrist.

That gruesome injury took him out for the rest of the NBA season that year.

Tony Allen makes a dumb mistake

The Boston Celtics seem to have their fair share of gruesome injuries but this one was completely the fault of one player. Tony Allen, a great defensive player, had the ball. The whistle blew on a foul and instead of just stopping the play, Allen decided to showboat and charged in to dunk the ball.

He tore his ACL coming down and that ended his NBA season.

Ray Allen's eye

Arguably, the most gruesome injury to an NBA star happened to another future Boston Celtics' star in Ray Allen while he was still in college. Allen was fighting for the ball with two defenders when one of them inadvertently brought his hand up. In what might be the most cringe-worthy moment in basketball history, Allen's eye actually bulges out as it dislocates from the socket. This video is not for the weak at heart.