West Ham midfielder Carlos Sanchez requires knee surgery and faces a lengthy spell on the sidelines.
The Colombia international, a £5million summer signing from Fiorentina, was hurt early on during the 8-0 win over Macclesfield in the Carabao Cup last week.
West Ham feared the worst at the time and striker Marko Arnautovic even held up Sanchez’s shirt as he celebrated a goal against Manchester United on Saturday.
And manager Manuel Pellegrini has confirmed the 32-year-old will have to go under the knife once the injury has settled down.
“Carlos had a problem with his knee ligament, maybe he will need a couple of weeks to be able to have surgery but he needs that,” said Pellegrini.
With Jack Wilshere still sidelined after an ankle operation Pellegrini is short in the centre with only Declan Rice, Pedro Obiang and skipper Mark Noble currently available.
Rice, Obiang and Noble are poised to form the midfield three once again when West Ham travel to Brighton on Friday night.
Meanwhile, Pellegrini insists Rice should not be pressured into deciding his international allegiance.
The 19-year-old remains absent from the Republic of Ireland squad for their forthcoming Nations League matches against Denmark and Wales as he is considering a switch to play for England.
“I am always talking with all players, Declan also,” added Pellegrini.
“He is a young player, we need to give him time to make a difficult decision, it is not easy.
“Both sides are close for him so we must not pressure him about his contract or what country he will play for.
“He can be a top player maybe some time in the future. He is learning a lot, always asking, he is very young but he has a huge future.”
Pellegrini also revealed striker Andy Carroll is back in light training after ankle surgery over the summer.
“Andy is working a little bit more in the gym and on the pitch so I hope that he will play as soon as he can but he needs a couple of weeks more,” said the Chilean.
