Soccer:Avram Grant is confident that West Ham will be able to survive without Robbie Keane after losing striker for at least a month with his a calf injury.

The Republic of Ireland striker made a successful start to his career at Upton Park, scoring on his debut after securing a six-month loan deal from Tottenham last month.

But the Hammers will have to do without the 30-year-old for key games against West Brom, Stoke and Liverpool after he picked up a calf injury in last weekend's 1-0 loss to relegation rivals Birmingham.

Hammers manager Grant had hoped the striker would be fit for tomorrow's crunch six-pointer at The Hawthorns, but it is now understood that the former Inter Milan hitman will be out until at least the middle of next month.

Grant acknowledged that Keane had made a huge impression on the team since signing but is confident that the likes of Demba Ba, Freddie Sears and Carlton Cole will be able to fill the void left by the experienced striker during his absence.

"I must say in a very short time, he has had a big, big impact on the team," said Grant. "He's very positive, his character, he's intelligent in his game, and he's a good player."

Grant boosted his strikeforce by signing Demba Ba on loan from Bundesliga side Hoffenheim last month.

The Senegalese hitman impressed when he replaced Keane last weekend, rattling Ben Foster's bar and causing the midlanders' defence problems throughout his 15-minute cameo.

Grant has had to contend with injuries to other key players this season and he is confident that Ba and the other strikers at his disposal will deliver if called upon at West Brom tomorrow.

Grant said: "If he (Keane) is injured, we need to play with the players we can play. We are used to this situation. Demba Ba is almost there. We will see how the situation is."