The Blues, enduring a miserable run of results under their new manager, were beaten 1-0 at home by Aston Villa.
In a game where Malo Gusto was sent off for the home team, Pochettino was furious at Colwill for not passing to teammate Mykhailo Mudryk who was in acres of space in the meantime.
Pochettino was seen yelling at Colwill and then had his head in his hands as Chelsea lost possession.
The former PSG and Tottenham coach is now under huge pressure at the West London club.
The Blues may have to start thinking about a managerial change if they cannot move away from the bottom half of the league table.