Under top-flight regulations, teams can only select 25 senior players in their squads but Pochettino currently has 32 on his books.
Tottenham travel to West Ham for their Premier League curtain-raiser on Saturday, and Pochettino is ready to make some big decisions about who he wants to keep at White Hart Lane.
"We have a week of hard work to go and there could be some changes," he is quoted as saying by Sky Sports. "But I already have in my mind the personnel important for the game.
"We currently have 32 players so we need to be clinical in our selection."
Pochettino has signed Ben Davies, Eric Dier and Michel Vorm since his arrival at Tottenham from Southampton in May.
He is also thought to be keen on bringing Southampton's Morgan Schneiderlin to his new club.
