Gottfried injured his knee during Sunday's 66-65 defeat against second- placed Newcastle. London's second defeat against the Eagles in seven days left the Towers clinging to a two-point lead at the top.
The London general manager, Rick Taylor, said: "The first examination of Martin's injury was inconclusive because the knee was too swollen for the specialist to make a diagnosis. There is no break or dislocation but it could be ligament damage. He is due another examination this weekend and until we know the extent of the damage, we can't guess."
London's only other previous meeting with Sheffield resulted 88-76 win for the Sharks at Wembley in late November, on the night they announced signing the former Cleveland Cavalier John Amaechi. Amaechi gets his first crack at Towers tomorrow and the coach, Chris Finch, said: "This time I'm hoping we may try to match them more inside now we have John. He's gone up against some big guys in his time."
Tonight at Birmingham's NIA, Newcastle defend a four-point lead against the Bullets in their quarter-final second leg as they attempt to join Towers, Sheffield and Greater London Leopards in the League Trophy semi- finals.
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