The star forward was lost in game five of the NBA Finals yesterday and likely for months to come.
Durant, who is three weeks from another foray into free agency, played for the first time since May 8, when he strained his right calf.
He was traveling to New York City on Tuesday (local time) for evaluations on the injury, league sources told The Athletic.
"Seeing your brother go down, trying to be there for him. It puts everything in perspective," Steph Curry said. "I'm kind of honoured the way he sacrificed, put his body on the line."
Durant exited in the second quarter after starting the game on fire. He had 11 points, two rebounds and one block to help the Warriors set the early pace in a game they ultimately won 106-105.
"I'm just devastated for Kevin," Warriors coach Steve Kerr said.
After the game, Bob Myers, the Warriors' president of basketball operations, confirmed that Durant has an Achilles injury.
"I don't know the extent of it," an emotional Myers said. "He'll have a MRI tomorrow."
Myers said medical and team personnel conferred several times to discuss whether Durant would play and made the decision to let him return.
"The people that questioned whether he wanted to get back to this team ... they're wrong," Myers said, fighting back tears.
Early in the fourth quarter, ABC's broadcast showed Durant leaving the building in a walking boot on crutches with his agent, Rich Kleiman.
ABC reporter Doris Burke said she spoke with Kerr returning to the court after halftime and he said of his message to the team, "You tell them to keep going, keep competing. Obviously we're all worried and thinking of Kevin right now."
Renowned former San Diego Chargers team doctor David J. Chao tweeted about Durant, "KD clearly grabbing at Achilles. Not saying complete tear but that is too low to be called calf. Bad news, his finals are done even if there is a game 7. Good news, should not affect his free agency."
In his first game since game five of the Western Conference semifinals against the Houston Rockets, Durant grabbed for his right Achilles and calf area while attempting to drive past Raptors forward Serge Ibaka with 9:46 to play in the first half. The Warriors were leading 39-34, and the home crowd erupted with cheers as Durant crumbled to the hardwood.
Ibaka and Kyle Lowry motioned to hush the fans as Durant was walked to the other end of the court and down the tunnel to the locker room.
The Raptors held a 3-1 series lead and were aiming to close out the championship series at home on Monday night.
Durant had missed nine games but was cleared to return to practice Sunday.
Kerr said pregame there would be no minutes restriction on Durant if he did play.
"You worry about the conditioning," Kerr said. "The skill, obviously, is undeniable. He's a guy who can get a shot off anytime he wants. ... He's Kevin Durant. If we have him out there, he'll be a threat. We know that."
Durant averaged 26.0 points, 6.4 rebounds and 5.9 assists per game in the regular season. During the postseason, he was producing 34.2 points, 5.2 rebounds and 4.9 assists per game entering Monday.
"The most difficult thing is just not being able to be out there with your teammates at the biggest time of the year," Kerr said pregame. "From that perspective, I have just felt bad for him. We all have. If you have a chance to play, go play and see what happens."
