Footage of the volatile 21-year-old limply tapping one serve over the net and then walking off court before Zverev had even struck his return sparked outrage across social media, with fans questioning the Canberran's commitment.
Kyrgios explained his "arm was a little sore" when questioned on the weak serves, but later posted on Twitter there were no excuses for his extraordinary defeat.
"Not good enough today on many levels, I'm better than that," he posted.
"I can go on about excuses but there are none. Sorry #StillAWorkInProgress."
Masur said he understood Kyrgios was only scheduled to play a couple more tournaments in 2016, both of them in France.
"He's got to have a look at it and say 'if I'm that burnt out and I've been travelling that much this year, maybe it's time to take a bit of a sabbatical'," Masur said.
Listen: Kyrgios on making the tour finals: I couldn't care less
Masur also questioned the wisdom of Kyrgios even taking the court against Zverev.
"If you've got nothing to give, if you're just feeling that low and who knows if there is an off-court catalyst and I'm not talking about this match in particular," said Masur.
"But there are things going on in the background of people's lives too and if you think that you haven't got the wherewithal to give your best effort it's probably best not to go on to the court because I think you do a lot of damage to yourself."
Listen: Kyrgios on fans - It's your choice to come see me
During the straight-sets loss to Zverev, Kyrgios engaged in verbal battles with the crowd, telling fans to "go home" after they'd told him to "respect the game, respect the people".
His post-match comments followed a similar line, with Kyrgios insisting he owed his fans nothing."They don't know what I'm going through," he said.
"I feel like if they knew what they were talking about they'd be on the tennis court and being successful as well."I don't owe them anything. It's my choice. If you don't like it, I didn't ask you to come watch. Just leave."
Listen: Nick Kygrios on the fans - I don't own them anything