The absence of the pair will raise concerns for manager Xabi Alonso, although there is an important caveat. Sky Sports cameras are only allowed to record the opening 15 minutes of Chelsea's training sessions, meaning Joao Pedro and James may have joined their team-mates later.
Both players completed the full 90 minutes of Saturday's 2-2 draw with Hull City at Stamford Bridge, with neither showing obvious signs of a problem.
Their potential availability for Brentford is therefore unclear, with Alonso expected to provide an update on Thursday.
Moises Caicedo was also absent from Tuesday's session and now appears unlikely to feature against Brentford.
The midfielder has endured a difficult start to the campaign after missing Chelsea's opening two matches before returning against Brighton, only to be substituted after 14 minutes. A calf issue subsequently kept him out against Arsenal, Leeds and Hull.
Meanwhile, Marco Palestra and Jordan Henderson were involved in training. Palestra has not played competitively since arriving from Atalanta after suffering a knock in training, while Henderson is nearing his first Chelsea appearance after recovering from a broken wrist.
Jamie Carragher believes Mikel Arteta is becoming the Premier League's equivalent of Sir Alex Ferguson after the Arsenal manager launched a strong public criticism of the officials following the victory over Sunderland.
Erling Haaland has praised Gianluigi Donnarumma as a "monster" after the Manchester City goalkeeper produced a crucial stoppage-time save to secure a dramatic derby victory over Manchester United.
Patrick Vieira has confirmed his commitment to Senegal after expressing his pride at taking charge of the national team ahead of the 2027 Africa Cup of Nations qualifiers.
Liverpool manager Andoni Iraola is considering changes for Tuesday's League Cup third-round clash with Tottenham Hotspur as he continues to assess how his squad handles a busy schedule.
