The 35-year-old made his debut for the club in a comprehensive 6-0 win against Barnsley in the competition last week but he faced a far bigger test on his Premier League debut in a 3-3 draw against West Brom on Saturday.
The Brazilian gifted the Baggies their second goal when his poor control allowed Callum Robinson to run free on goal.
Though Silva was unlikely to feature against Spurs due to his ongoing search for match fitness, the Brazilian was nevertheless left out of Frank Lampard’s squad to face Spurs at the Tottenham Hotspur Stadium.
Mourinho had a number of selection dilemmas of his own given Spurs’ hectic fixture list and he was asked about his decision to leave Dele Alli out of his matchday squad.
However, the former Chelsea boss didn’t take too kindly to the line of questioning and used Thiago Silva’s absence following his mistake on the weekend to hit back.
‘No Dele Alli, no Sonny [Heung-Min Son], no Giovanni Le Celso, said Mourinho.
‘I’m not going to speak about the players that are not here.
‘Are you going to ask Frank [Lampard] about why Thiago Silva is not here? Is it the mistake he made or another reason?’
The veteran was handed an initial one-year deal but a clause in his contract means he can extend it by a further 12 months.
Kurt Zouma and Fikayo Tomori start as a pairing in north London in Silva’s absence.