Already without long-term injury victim Michael Dawson, the Spursboss lives with constant worry that King's career could suddenly end ifhe keeps playing without training.
Cause for concern: Spurs boss fears for Ledley King
With all four teams in their group on identical points and goal difference, Tottenham face Dutch champions Twente Enschede in arguably their most important fixture for two generations.
'Only Ledley will know when he's had enough,' said Redknapp.
'He wants to play and we can't stop him. In the long term, of course, I worry. I don't want to see him end up as a cripple. Playing football is one thing but they can have ops and knee replacements now and he might need something like that.'
West Ham 1 Tottenham 0: Piquionne winner eases pressure on GrantNutty Professor! Stress has turned Wenger as crazy as rest, says HarryTOTTENHAM HOTSPUR FC: All the latest news from across the web