While Clarke is set to be one for the future, Ndombele can expect to be integrated straight into Pochettino's squad next season.
According to Sky Sports, Spurs have completed the signing of the France global for a club-record £65million fee.
Clarke found it impossible to turn down a move to Spurs and is likely to complete his switch by the end of the week.
The 18-year-old Thorp Arch academy product enjoyed his breakthrough campaign under Marcelo Bielsa last season.
Named Leeds' Young Player of the Year in 2018/19, Jack featured as a substitute on a number of occasions in the closing weeks of the season, including both legs of the Whites' Championship play-off semi-final clash with Derby County.
After signing from Ligue 2 side SC Amiens in 2017, Ndombele made 96 appearances for Lyon, scoring four goals and providing 16 assists, and played an instrumental role in the club achieving a third-place finish in Ligue 1 last season.
The 22-year-old passed a medical on Tuesday after weeks of talks finally bore fruit on a deal which smashes their transfer record.
"Obviously (Mauricio) is one of the best coaches in the world, a top, top manager".
Roberts is hyped about Ndombele potentially arriving and believes Spurs will be signing a special talent.