Ntlhe, sidelined since suffering a broken ankle against Sheffield Wednesday on November 3, played 45 minutes of a friendly against Stevenage on Wednesday afternoon.
The South African left-back, 19, conceded a penalty in the game but goalkeeper Joe Day saved the spot-kick.
Fellow defender Craig Alcock played the full 90 minutes after a recent spell out with a knee injury.
Seventeen-year-old striker Shaq McDonald, a recent signing from Evo-Stik Division One side Chasetown, scored both Posh goals in a 2-2 draw.
