Ba, who failed a medical at Stoke earlier this month, has agreed a deal until 2014 with the struggling Hammers after coming through extensive checks on a knee problem. West Ham had initially been lining up a loan move for the 25-year-old. The transfer fee is undisclosed but is heavily dependant on appearances. Ba is West Ham's third signing of the transfer window, following Wayne Bridge's arrival on loan from Manchester City and Gary O'Neil's move from Middlesbrough. But with West Ham bottom of the Premier League, manager Avram Grant is looking to bring in more firepower with Tottenham striker Robbie Keane among his targets. "We have to look at the general make-up of our squad and there are areas high up the pitch (we are looking at)," said Hammers coach Paul Groves. "We have brought in Demba Ba. We have Carlton Cole, Zavon Hines and Frederic Piquionne. We could possibly do with another one. "It is always good to have options in those forward areas, where people could perhaps produce something out of nothing. "That is nice for any football club to have any maybe on the odd occasion we could have done with that." Ba, who was born in Paris, has won eight caps for Senegal and he scored 40 goals in 103 appearances for Bundesliga side Hoffenheim. "He has proved himself in a top league. He is a handful, he scores goals and for us he is a good addition," said Groves. Ba is eligible to play against Nottingham Forest in the FA Cup on Sunday, although he is short of match fitness because the German league has been on a winter break.
