LONDON -- Nemanja Vidic trained with Manchester United for the first time on Thursday after completing his move from Spartak Moscow.
United declined to say what they had paid for the 24-year-old Serbia & Montenegro defender but British newspapers reported the fee as $12 million.
"The player has signed a four-and-a-half year contract which will see him at the club until June 2010," United said in a statement.
Vidic is eligible for United's FA Cup third round match against minor league Burton Albion on Sunday.
Vidic joined Spartak from Red Star Belgrade in 2004 and is part of Serbia & Montenegro's "famous four" defence which conceded just one goal in successfully qualifying for the 2006 World Cup finals in Germany.
United manager Alex Ferguson told the club's television channel MUTV: "Good defenders win you things and this lad is really natural and athletic."