Sarr returned to Tottenham after Senegal's second-round exit from the continental tournament with a loss to Ivory Coast in penalties on Monday.
"Pape Sarr is back ... he had a long trip. We'll assess him after training but fair to say he'll be involved, although not sure what extent," Postecoglou told reporters ahead of Saturday's visit to Everton.
The club had no new injury concerns after Wednesday's 3-2 win over Brentford, the manager said.
"Obviously it's a short turnaround and the lads are still recovering from that so we haven't done too much training-wise," he added.
Tottenham achieved their January transfer targets after bringing in forward Timo Werner on loan from RB Leipzig and signing defender Radu Dragusin from Genoa, Postecoglou said.
"From our perspective, we had some clear objectives in there. One was we had a real gap at centre-back, particularly after letting Davinson Sanchez go after the window closed last time and getting Radu Dragusin early was great," he said.
"Obviously getting Timo Werner early as well was also excellent for us... the beauty of getting them early is they have made a contribution.
"If we had left it to the last day yesterday it still takes time to settle. Both of them have settled well," he added.
Werner has made two starts in the league for fourth-placed Tottenham since joining the club last month, while Dragusin has made two appearances off the bench.
