Mourinho said Alderweireld and fellow defender Serge Aurier did not travel to St James’ Park after only training on the day before the game following this week’s internationals.
“They were fit, yeah, but they reported for training only yesterday,” the manager told his post-match press conference.
“They went for their national teams and they didn’t make the Covid tests on time to be in the training session on Thursday, not even on Friday. They come only yesterday.”
But sources with knowledge of the situation insist Alderweireld reported to Hotspur Way on Wednesday afternoon, having played in Belgium’s win over Belarus in Leuven on Tuesday and travelled back to London in the morning.
The centre-half is understood to have been tested on Wednesday and trained individually, before joining the squad for sessions on Thursday, Friday and Saturday.
It is thought Aurier and Steven Bergwijn, who was also not selected in the travelling squad, may have reported back from international duty too late to play a full part in preparations for the match but Mourinho’s comments about Alderweireld have left sources baffled.
“I don’t want to say indiscipline,” Mourinho added, when pushed on the absence of Alderweireld and Aurier.
“I don’t want to say that. This is what it is. The players that landed in London on Wednesday after internationals and the ones that played in London – as in the case of the English boys – they had the tests and they could immediately be in training on Thursday and so Thursday, Friday and Saturday.
“And they [Alderweireld and Aurier] couldn’t. They appeared only yesterday.”
Alderweireld and Aurier missed Spurs’s 2-0 win over Aston Villa before the international break through illness and Mourinho stuck with the same XI against Newcastle, with young defenders Japhet Tanganga and Joe Rodon starting.
Joe Willock’s late strike earned a deserved point for Steve Bruce’s struggling side, who took the lead after Joelinton capitalised on errors from Tanganga and Davinson Sanchez.
Harry Kane’s quick-fire double had given Spurs a 2-1 lead going into the final five minutes.
Alderweireld last featured for Spurs in the 2-1 defeat to north London rivals Arsenal on March 14 but played 90 minutes in all three of Belgium’s matches last week.