Samuel was prolific for the Royals' Under-18s last season and, having been awarded a professional deal in the summer, has continued where he left off for their Under-21s this term.
As a result, the England U19 international was drafted into Reading's first-team matchday squad and duly made his Premier League debut as a second-half substitute in the 3-0 defeat at Sunderland in mid-December.
Meanwhile, left-back Dan Potts has seen his loan spell with the U's cut short after he was recalled by parent club West Ham.
Potts was due to remain at the Weston Homes Community Stadium until January 27.
