Kerr announced the news following his team's 114-110 series-ending loss to the Toronto Raptors in Game 6.
Durant revealed that he had successful surgery and is currently recovering.
The Warriors forward suffered a right calf strain in Game 5 of the Western Conference semis against the Houston Rockets. He missed the following nine contests but returned for Game 5 of the NBA Finals. He scored 11 points in just 12 minutes before suffering the Achilles injury.
Durant has one year left on his current contract provided he picks up a $31.5 million player option. If not, he will become a free agent.
Although Durant is out for an extended period of time, he shouldn't have a shortage of teams looking to acquire him whenever he hits the market.
David Aldridge of The Athletic reported the following on Tuesday.
"League sources Tuesday made it plain: Durant’s injury, whether in the short-term or longer, has done little to cool the ardor of his most dogged free agent pursuers," Aldridge wrote. "The likelihood remains that all of the New York/L.A. teams will stay in the hunt for Durant beginning on the afternoon of June 30."
That doesn't come as too much of a surprise given his sterling resume. The 10-time All-Star and one-time NBA MVP has averaged 27.0 points on 49.3 percent shooting and 7.1 rebounds per game during his career.
Provided he does miss the 2019-20 season, he'll take the court next at 32 years old. Granted, that means he's far closer to the end of his career than the beginning, but he could still produce a few seasons close to his peak.
It's not uncommon for stars to dominate into their mid-30s. Of note, Kobe Bryant averaged 27.3 points per game after turning 34, and LeBron James just posted 27.4 points and 8.5 boards at the same age.
Durant would be coming off a serious injury, of course, bur ex-San Diego Chargers team doctor David Chao wrote a piece for the San Diego Union-Tribune that in part expressed optimism for the Warrior's future.
"This is a devastating injury for a basketball player, but Durant can return to be the same or very close," Dr. Chao wrote. "This does not mark his downfall as an elite player."
Teams feel the same way if Aldridge's report is any indication, so we could certainly see Durant return to form in 2020. The biggest question is what uniform he will be wearing.