"Kobe is a big question mark," said General Manager Mitch Kupchak to Colin Cowherd on ESPN Radio on Thursday. "We're very optimistic. He's getting treatment every day. He's in the facility right now, but he hasn't been on a basketball court."
Bryant was injured April 12 in a win over the Golden State Warriors. He had surgery the following day.
On a recent trip to China, Bryant said he has "shattered" his recovery timetable, which was originally announced as six to nine months.
"Our best player, one of the best players to ever play the game, is recovering from an Achilles' tendon tear," Kupchak said. "You have a player who is up in age and just had a devastating injury."
Bryant turns 35 on Aug. 23.
Veteran point guard Steve Nash, now 39, has also spent most of the summer rehabbing his back, hip and hamstring issues that kept him sidelined late in the season.
"Steve, my understanding, is very close to 100%, but he's not as young as he once was," Kupchak said.
Bryant is heading into the final year on his contract but Kupchak can envision the All-Star guard continuing with the team for multiple years.
"If he can play at a high level, I can't see any reason why he wouldn't be," Kupchak said. "There really has been no discussions beyond next year."