Fabianski was replaced by sub goalkeeper Roberto during the game at the Vitality Stadium after going down in the 34th minute. Now, Pellegrini has confirmed Fabianski may require surgery to fix the problem, which could keep the former Arsenal man out for almost three months.
Pellegrini revealed in his press conference, as quoted by the West Ham website: "About Lukasz, the medical staff will decide today or tomorrow if he will have surgery or if he will recover without surgery. Either way, it will be less than three months he is out.
"For the moment, we have Roberto as goalkeeper and I trust a lot in him. I am confident he will have good performance. We also have David Martin, who has good experience."
Fabianski has been instrumental to West Ham's upturn in form, with Premier League stats showing that he made the most saves last season. He has been examined throughout the week by medical staff, and fortunately the injury is not as bad as first feared.
This leaves West Ham with two relatively fresh faces competing for the back-up job. They brought in both Roberto and David Martin on frees over the summer and the Spaniard seems to have the edge, having played twice in the Carabao Cup, although he did concede four to League One Oxford United.
Nevertheless, this will undoubtedly be a huge blow for the Hammers, who have started so well. Pellegrini called Fabianski one of the best three goalkeepers in the league before last week's clash with Bournemouth, but they will now have to go up to three months without their number one.
Source : 90min