Mauricio Pochettino was delighted to see Chelsea win the Premier League Summer Series but his joy was overshadowed by an injury to Trevor Chalobah.
Centre-back Chalobah, 24, was introduced in the second half last night as the Blues beat Fulham 2-0 in Washington to follow-up a 4-3 win over Brighton and a 1-1 draw with Newcastle.
Yet he lasted just 15 minutes before being forced off.
After seeing goals from Thiago Silva and Christopher Nkunku see off the Cottagers, Pochettino said: "I hope it's not a big issue but we need to assess.
"It doesn't mean it is big. It was a precaution but we need to assess him the next few days. We don't believe it is big but hope also."
Having seen Chelsea pick up seven points from nine during the inaugural Summer Series, Pochettino is pleased with how his young squad is shaping up.
The Blues kicked off their tour of the United States with a 5-0 win over Wrexham and will end it on Wednesday night when they face Borussia Dortmund in Chicago.
Poch added: "It is a busy time but I think we are doing a good job — the players and the staff.
"It has been a busy four games in a very short period of time and now we play in Chicago against Dortmund and we need to continue.
"We keep going and prepare the team to arrive in the best condition for the Premier League."
Silva opened the scoring with a fine header from Ben Chilwell's corner after 20 minutes to cap a dominant opening from the Blues.
Fulham offered little in terms of an attacking threat and Nkunku, 25, scored what proved to be the last goal of the game when he tapped home from close range with 41 minutes on the clock.
It was the Frenchman's third goal since joining the Blues from RB Leipzig.
DacGeP0Ooik
