The talented English player, who was named Chelsea's captain at the outset of the 2023-24 season, was substituted in the 76th minute during Sunday's 1-1 draw against Liverpool in the Premier League.
Mauricio Pochettino, the head coach of the Blues, commented following the match against Liverpool that James's substitution was a precautionary measure in light of his fitness struggles during the previous season.
"Because he was tired. You need to see from where he came. The first thing we did when we arrived was to assess and analyse all of the players from the past," Pochettino told reporters.
"He was injured for three or four months. This pre-season was tough for him, we didn't want to take any risk and that is why at 80 minutes, we wanted to avoid the risk."
However, as per journalist Nathan Gissing, Reece James could potentially be entering a period of inactivity due to a hamstring concern. It remains unclear whether the defender sustained the issue during the match against Liverpool on Sunday or encountered setbacks in a training session earlier this week.
According to Gissing, the 23-year-old is set to undergo a scan on Thursday afternoon to assess the extent of the damage, which might lead to him missing several weeks at the start of the season.
Reece James had already missed the conclusion of the previous season due to a hamstring problem, and he also had spells on the sidelines due to a knee injury in the 2022-23 campaign. This setback raises significant concerns for Chelsea, who are striving to manage the fitness of a player who participated in just 16 Premier League games last season.
With a forthcoming league fixture against West Ham United scheduled for Sunday afternoon, it appears highly probable that the captain will be absent for that match.
Looking ahead, Chelsea is slated to take on Luton Town in the Premier League on August 25 before wrapping up the month with a clash against AFC Wimbledon in the second round of the EFL Cup.
Adding to their injury woes, the Blues are currently without the services of Christopher Nkunku, Benoit Badiashile, Wesley Fofana, and Trevoh Chalobah.
Reece James's absence might prompt Pochettino to reconsider his tactical setup. The team's new manager opted for a back five formation against Liverpool, with James and Ben Chilwell occupying the wing-back roles.