The France international is eager to play at the tournament in Russia and he was considering a move away from the north London outfit.
After joining Spurs for £30 million in the summer of 2016, Sissoko has failed to kick on and his performances have been criticised.
He only made eight starts last season but Spurs failed to find a buyer and Sissoko is now hoping that his displays this year will be enough to impress France boss Didier Deschamps.
Sissoko has made four appearances so far this season and Pochettino insists he was happy to keep the former Newcastle man.
Pochettino told reporters: "Every player that maybe wasn't involved too much in my plans last season, all the players try to play more.
"And I am so honest with you, the player [Sissoko] was the first [one] interested to move or to leave because he wanted to play more in a season that has the World Cup at the end.
"But I think maybe that possibility didn't exist and I was more than happy for him to stay and give him the possibility to play."