New Tottenham signing Clinton N'Jie did not feature against Leicester.
Spurs drew 1-1 with Leicester City, and new signing N'Jie did not even make the substitute's bench.
Pochettino told Tottenham's official club website that N'Jie was unable to feature because he was had not been in the country.
He explained that the Cameroonian attacker had been sorting out work permit related issues, and was not considered ready.
The Argentine said: "He was in France for his work permit and maybe next week he will be available.
"First, he needs to train more with the group."
As a regular international for Cameroon there were not expected to be any complications preventing N'Jie from getting his work permit, but clearly some paperwork still needed to be completed.
Tottenham's club website confirmed on Friday that N'Jie has been granted his work permit.
The London Evening Standard reported a day earlier that N'Jie had been in Paris on Tuesday and Wednesday and Spurs were to take a look at him in training the subsequent days.
Pochettino was quoted: "It was his first day, so we need to assess him today and Friday. We have to wait and see on Friday if he can be in the squad for the Leicester game on Saturday."
Clearly they decided against rushing the attacker, but these issues would not be arising at this stage of the season with games already underway had Spurs completed the deal mid-summer.