Chelsea are set to be without Ruben Loftus-Cheek in the Europa League final this month after the England midfielder suffered a suspected achilles injury during the club’s ‘Final Whistle on Hate’ charity match against New England Revolution.

Loftus-Cheek, a half-time substitute at the Gillette Stadium, which was attended by Roman Abramovich, fell awkwardly within 20 minutes of his introduction in the visitors’ 3-0 win and was left in clear agony. He was helped back to the dressing room for further treatment by two of the medical staff, and departed the stadium on crutches and wearing a protective boot on his left foot, returning to the team’s base in a car, away from his teammates.

The 23-year-old was due to be named in Gareth Southgate’s England squad on Thursday for next month’s two-game Nations League tournament in Portugal. Club and country will await results of further medical tests. There were suggestions from teammates in Boston that Loftus-Cheek’s injury may well rule him out until next season, with his loss realising the worst fears of the head coach, Maurizio Sarri.

While supportive of the good intentions around the friendly fixture, which raised around £3.1m to combat discrimination, with around 27,000 attending the match, Sarri had been unconvinced as to the timing of a game tagged on to a draining season. Chelsea face Arsenal in Baku on 29 May, and the Italian had hoped his players might benefit from a more prolonged rest rather than flying immediately to the United States upon the conclusion of the Premier League campaign.

Sarri, who has been suffering from a stomach bug, did not comment publicly on the four-day tour. He was absent as the 23 touring players and the chairman, Bruce Buck, visited a Holocaust Memorial on Tuesday but was on the touchline as his team ran out comfortable winners against the Major League Soccer side with two goals from Ross Barkley and another from Olivier Giroud, with Abramovich visiting the dressing room post-match.

Chelsea are confident N’Golo Kanté will have recovered from a hamstring complaint to feature in Baku but Loftus-Cheek’s absence constitutes a considerable blow. The midfielder has enjoyed the best form of his Chelsea career since overcoming the latest bout of back trouble and has been a driving force over recent weeks and contributed 10 goals in all competitions. Four of those came in the Europa League, in which he has been a regular.

The game against Arsenal is likely to be Gonzalo Higuaín’s final appearance in a Chelsea shirt, with the club having decided not to trigger an option to extend his loan or make his move from Juventus permanent. The Argentinian, whose signing was championed by Sarri, has five goals in 21 appearances since joining in January on an initial six-month deal. It would have cost Chelsea €18m (£15.7m) to extend that to 2020, or €36m to sign him outright, but the 31-year-old is expected to return to Turin.

Giroud, the Europa League’s joint leading scorer, is likely to stay, with the club to trigger a one-year option on his deal, while attempts will be made to secure Mateo Kovacic from Real Madrid on a permanent deal, depending upon the club’s ability to have their two-window Fifa transfer ban frozen by the court of arbitration for sport.