West Ham United manager Manuel Pellegrini will be without his number one goalkeeper Lukasz Fabianski for at least two months.

Fabianski was injured in the Premier League 2-2 draw away to Bournemouth last Saturday as he attempted to take a goal kick and was then substituted in the 34th minute.

The 34-year-old has since been diagnosed with a torn hip muscle which could keep him sidelined until December.

The news comes as a huge blow to the Hammers who have had a very good start to the season, winning three matches and drawing three from their opening seven games to lie fourth in the table.

The Poland international netminder, who was the 2018/19 club player of the season, and centre-backs Issa Diop and Angleo Ogbonna have been key to the Londoners good form.

West Ham host Crystal Palace in their next game which should mean a first Premier League start for new signing Roberto.

The 33-year-old former Espanyol goalkeeper was a free transfer signing last summer and has played in both EFL Cup games for the Hammers this season while he replaced Fabianski at Bournemouth on Saturday.

"It’s part of the position that you have the situation where you are not in the first eleven, but we have to be ready every time as these sorts of things can happen, so I’m happy for my debut in the Premier League as it is something every player wants to do at least once in their life," said Roberto after the game. "I am also happy with the way the team played."

Roberto is hopeful that he can help West Ham keep their impressive early-season momentum.

"Yes, I work every day to make everything possible and now, if I have this chance, I feel absolutely ready, so I am not feeling nervous," added the Madrid native.

"Well, we know our target for this season is to be in the highest part of the table and I think we are in the way to do it. The team is playing well and behaving well and I think we are in a good way."