Martinez was named in the squad for his country's two November internationals, and he had travelled to South America after representing Man United in the Premier League against Leicester City on Sunday.
However, it was later revealed that the centre-back had pulled out of the squad, with Argentina medical staff believed to have described the issue as 'a significant hip injury'.
Martinez therefore withdrew from the camp, but there have been contrasting reports surrounding the exact nature of the issue and whether or not he is facing a period on the sidelines.
Scaloni, speaking ahead of Argentina's clash with Paraguay on Thursday, revealed that Martinez was suffering with pain in his back, and the lengthy journey to South America had aggravated the issue.
Scaloni clarifies Martinez issue amid recent confusion
"We didn't expect the case of Lisandro. We saw that he had suffered a blow to his back, but apparently, he had no problem, just pain. When he arrived here, the pain increased a bit, he underwent tests and is not fit to be here," said the manager.
Man United are yet to issue an update on Martinez, who required treatment in the latter stages of his side's Premier League clash with Leicester after taking a heavy knock.
At the time, it did appear that the centre-back would need to be substituted, but he completed the 90 minutes, suggesting that it was an impact injury which he had managed to shake off.
Man United will now be sweating over his fitness ahead of their return to Premier League action, with Ruben Amorim set to take charge of the Red Devils for the first time against Ipswich Town on November 24.
Which players are currently injured for Man United?
The club's injury problems have eased at the perfect time for Amorim, with Tyrell Malacia playing 45 minutes for the club's Under-21s against Huddersfield Town in the EFL Cup on Tuesday night.
The minutes were Malacia's first since May 2023, while Luke Shaw and Leny Yoro are back in full training, with the pair closing in on their first appearances of the 2024-25 campaign.
Kobbie Mainoo has also been back in training, while Mason Mount, Christian Eriksen and Antony have returned from recent problems, further boosting Amorim's options ahead of the Ipswich clash.
Harry Maguire, though, is still working his way back from a muscular problem, while Toby Collyer continues to recover from a muscular injury of his own, and it is unclear at this stage when the two players will be available.