The England left-back made his first start for four months against Middlesbrough on Tuesday, playing 65 minutes of a 6-1 win in the Carabao Cup semi-final second leg, but he may not be risked in tomorrow's FA Cup fourth round game.
Chilwell has had a spate of injury issues in recent seasons and is keen to avoid a recurrence of his hamstring problem.
Asked whether Chilwell could start again on Friday, Chelsea boss Pochettino said: "The challenge was from the pre-season to build his fitness.
"Of course, improve his offensive phase and defensive phases. That was the challenge for us to make him a more complete player.
"Of course, he is an important player when he is fit and can cope with the 90 minutes, but on Tuesday, he cannot cope, as he asked to go out after 10 or 15 minutes to build his fitness.
"We have doubt if he can start tomorrow to assess if he can cope with another game after three days. That is a massive decision because we want to build his confidence, fitness and be consistent playing for the rest of the season.
"We are working really hard with the medical staff in the performance area to take the best decision. If he cannot start tomorrow, he will be on the bench and help in the second half."
Pochettino confirmed that Christopher Nkunku and Malo Gusto are both out but could return against Liverpool next week, adding: "No, they could be available for Liverpool on Wednesday.
"They could be but we need to see how they evolve in their progress for the next few days. We are positive but they will not be available tomorrow."
The January transfer window closes next Thursday but the Blues have been cautious so far, having signed £1billion worth of players in the last 18 months.
Pochettino denied that Chelsea need any major signings as the club assesses any opportunities in the market.
“No, not really," he replied when asked whether the club need any more players.
"We are desperate to win the title, not desperate to sign players. I am happy with the players in the squad, but if something happens, because you know very well that the last week is the most dangerous week, we need to be ready for anything that can happen in the squad.”