It comes after the England star suffered a ruptured Achilles in a end of season friendly in Boston with Chelsea fearing he will out for up to a year.
Loftus-Cheek will miss Chelsea’s Europa League final against Arsenal on May 29 – a match that could be Sarri’s last as Blues boss.
Express Sport understands Sarri fears the sack and could be gone this summer, one way or another.
For Loftus-Cheek, a period of recovery awaits with the 23-year-old also missing England’s Nations League campaign this summer.
He went down in agony during the second half of Chelsea’s ‘Final Whistle on Hate’ game against New England Revolution which they won 3-0.
He was carried off by two members of Chelsea’s medical team and left the Gillette Stadium on crutches, wearing a large protective boot on his left foot.
England manager Gareth Southgate bemoaned the injury with the former defender admitting Loftus-Cheek would have been in his squad to head to Portugal.
Southgate said: “I went to bed last night and Ruben is in the squad and playing brilliantly and now it is a huge disappointment for him.
“He misses now a major European final and a brilliant opportunity with us.
“In particular he has really come on in the last few months and looked strong and playing with a lot of confidence and I am really disappointed for him in particular.”
It will be Sarri’s worst nightmare with the Italian having previously voiced his concerns over the trip across the Atlantic.
Speaking after their Europa League semi-final victory over Eintracht Frankfurt, the Italian said: “We have to recover energy because we are really very tired.
“Unfortunately we have to go to the United States. I think in this moment we need to rest then we have 10 days to prepare for the final.”
Chelsea confirmed the midfielder will undergo surgery on his Achilles on Thursday.
They posted a statement saying: “Ruben Loftus-Cheek has seen a specialist today (Thursday) and will have surgery on his ruptured Achilles’ tendon this evening.
“The Chelsea midfielder left the pitch during the second half of yesterday’s game in Boston, USA.”