Reece James has been ruled out of Chelsea’s weekend visit to West Ham and could face several weeks on the sidelines after sustaining a hamstring injury in training. James, 23, was made club captain by new manager Mauricio Pochettino in the summer, but his first game leading the side ended early when he was replaced in the second half of the 1-1 draw with Liverpool. Aftewards Pochettino insisted James was suffering only from fatigue and would be fit for the Blues’ visit to the London Stadium. But the defender has now picked up a muscle strain that adds to his long line of injuries disrupting his progress at Stamford Bridge. A statement said: “Reece James is starting rehabilitation having undergone assessments on an injury sustained in training this week.” Meanwhile, Chelsea have completed the signing of 19-year-old defensive midfielder Romeo Lavia from Southampton on Friday after agreeing to a reported transfer fee of £58m. The Belgium international signed a seven-year deal after reportedly rejecting a proposed move to Liverpool. The spending spree at Stamford Bridge continues with Lavia arriving just days after Chelsea signed Ecuador midfielder Moises Caicedo from Brighton for £115m. Caicedo's signing took Chelsea's spending on players to almost £1bn in 15 months under its new American owners. The highly rated Lavia has played only 29 times in the Premier League. “I’m really happy to join Chelsea and be a part of this exciting project,” Lavia said in Chelsea’s announcement. “It’s an amazing football club with a great history and I’m really excited to get started. I can’t wait to meet all my new teammates and build a chemistry together to achieve great things together.”