Gordon Hayward Free Agency, NBA Free Agency 2017
Apr 30, 2017; Los Angeles, CA, USA; Los Angeles Clippers guard Raymond Felton (2) defends Utah Jazz forward Gordon Hayward (20) as he drives to the basket in the second period of game seven of the first round of the 2017 NBA Playoffs at Staples Center. USA TODAY Sports / Jayne Kamin-Oncea

Boston Celtics forward Gordon Hayward is likely out for the remainder of the season after suffering a horrific leg injury during an opening night game against the Cleveland Cavaliers Tuesday. Hayward, Boston's prized free agent acquisition in the summer, was stretchered off the floor at Quicken Loans Arena after fracturing his ankle barely five minutes into his Celtics debut.

The injury occured when Hayward's left leg bent awkwardly while going up for an alley-oop pass. The All-Star wing collided with LeBron James and collapsed under the basket.

After the game, Celtics coach Brad Stevens said Hayward fractured his tibia and dislocated his left ankle. Hayward will undergo emergency surgery on Wednesday at New England Baptist Hospital, according to ESPN's Michael Wilbon.

The Celtics were expected to turn into championship contenders after acquiring Hayward and All-Star point guard Kyrie Irving, who notched up 22 points and 10 assists in his debut. Following Hayward's injury, the Celtics are no longer projected to make a run at the Cavaliers for the Eastern Conference crown.

Kyrie Irving: 'One of the worst injuries I've ever seen'

After the game, Irving called Hayward's injury "one of the worst" he had ever seen. "It's tough. I've seen a few injuries in my career and I've had a few. Probably two of the worst ones I've been in the game watching -- one was (Paul George) at (Team) USA (scrimmage) and this one tonight. It's not a great sight to see, but you gotta pick yourself up. Just keep on fighting, man. We understand that (Hayward), God willing, will be fine, and we're going to continue to pray for him and be there for him as best we can."

LeBron James, who started the new season with a stunning stat line of 26 points, 16 rebounds, 9 assists and 2 blocks, empathised with Hayward. "I've seen a couple of injuries like that in my lifetime. I've seen Paul George when it happened to Paul. I was watching the game with Shaun Livingston when it happened when he was with the Clippers. I was watching NCAA basketball when Kevin Ware was at Louisville. Those are the injuries that you never seen coming and you never want to happen, no matter who it is, no matter what the stature, no matter how much competitive nature that you have. It's just very unfortunate."

The 2017-18 NBA season got underway Tuesday with two marquee matches: pitting Cavs and Celtics against each other in an Eastern Conference finals rematch, besides a clash between the Golden State Warriors and Houston Rockets. The Cavs prevailed 102-99 in a close affair but Hayward's injury dominated the news bulletin. The Celtics will return home to host the Orlando Magic on Wednesday (Thursday in Australia). Meanwhile, the Cavs will face the Milwaukee Bucks in an away game a day later. Stay tuned for the latest Gordon Hayward injury update.