Townsend, 24, has come up through the ranks at White Hart Lane, but has recently struggled for first-team football under Pochettino, with just 64 minutes of Premier League action to his name this term.
Having failed to start a Premier League game, Townsend is now growing increasingly frustrated on the sidelines at White Hart Lane, and that unhappiness appeared to boil over on Monday night.
Townsend was again left on the bench as Pochettino instead chose to bring on 18-year-old midfielder Joshua Onomah for his Premier League debut, and Townsend was then involved in a stunning row with fitness coach Nathan Gardiner, as reported by the Daily Mail.
Spurs are back in action on Thursday night as they take on Anderlecht in the Europa League, but Townsend won't be taking any part.
Manager Pochettino has spoken to The Mirror about the incident between Townsend and Gardiner, and has decided that winger will be left out of the squad completely and won't train with the first-team, as he must learn the consequences of such behaviour.
"You know (what happened) because it was public with the picture and it is impossible to hide but this is a private matter. Always there are actions and a consequence," said Pochettino. "Did he train? With the group no and he is not available to be selected for tomorrow. He is not in the squad. It is because of Monday. When you behave in the wrong way, always you need to pay," he added.
It now remains to be seen whether Townsend can get back in the Spurs squad for Sunday's trip to North London rivals Arsenal, but things are turning sour for the England international - and a January exit, whether loan or permanent, could be the best solution for all parties.
What is the next step for Tottenham and Townsend?