The six time champion suffered a recurrence of the injury after he was defeated by Korean world No 58 7-6 (7-4) 7-5 7-6 (7-3) against the 21-year-old.
Djokovic, who missed the second half of the 2017 campaign, had limited competitive match preparation to the season’s opening Grand Slam and admitted his encounter with Chung had proved “too much to deal with”.
“Unfortunately, it’s not great,” said Djokovic, who decided against undergoing surgery during his enforced break from the game, in his post-match press conference.
“At the end of the first set it started hurting more. So I had to deal with it until the end of the match.
“I have to reassess everything with my team, medical team, coaches and everybody, scan it, see what the situation is like. The last couple of weeks I played a lot of tennis. Let’s see what’s happening inside.
“It’s frustrating, of course, when you have that much time and you don’t heal properly. But it is what it is. There is some kind of a reason behind all of this. I’m just trying my best obviously because I love this sport.”
Chung became the first Korean male or female player to reach a Grand Slam quarterfinal and Djokovic was full of praise for his opponent, who impressed with his composure on the big points.
Earlier, Roger Federer maintained his record of not having dropped a set with a straightforward victory over Marton Fucsovics to reach the quarter-finals.
The 25-year-old Hungarian was a surprise face in the fourth round and acquitted himself well on Rod Laver Arena but ultimately proved no match for the defending champion, who won 6-4 7-6 (7/3) 6-2.
The victory sends Federer through to the last eight in Melbourne for the 14th time and 52nd overall in grand slams, where he is likely to be more severely tested by Tomas Berdych.