Chelsea defender Ben Chilwell was forced off with an injury in Wednesday's 1-0 win over Brighton & Hove Albion in the EFL Cup.
After being used as a substitute in Sunday's defeat to Aston Villa, Chilwell returned to the starting lineup for the third-round tie.
Chilwell, who wore the captain's armband, played the majority of the game as Nicolas Jackson scored the decisive goal in the second half.
However, the England international appeared to sustain an injury during a tussle with former Chelsea player Billy Gilmour.
Chilwell was forced off after receiving treatment, leaving Chelsea to complete the remainder of the contest with 10 men, having already used all of their allotted spaces for substitutions.
Asked about Chilwell's injury after the game, Pochettino told reporters: "We need to assess tomorrow but I think it was his hamstring."
Chilwell will hope that the injury is not too serious after he missed several months of the 2022-23 season due to hamstring issues.
The 26-year-old has been used regularly by Pochettino this term, starting the first four league matches of the season, before appearing as a substitute in the next two.
Pochettino is already without a number of first-team players, and he will be concerned that Chilwell could add to a lengthy injury list.
Defenders Reece James, Benoit Badiashile, Wesley Fofana and Trevoh Chalobah are all sidelined for the Blues.
They are also joined in the treatment room by Romeo Lavia, Carney Chukwuemeka, Christopher Nkunku and Marcus Bettinelli.
In addition to several injury absentees, Chelsea will also be affected by two suspensions for Monday's away meeting with West London neighbours Fulham.
Malo Gusto is unavailable after being sent off against Aston Villa on Sunday, while Jackson is suspended for an accumulation of yellow cards. body check tags ::