Dwain Chambers yesterday withdrew from the 200m, citing a calf injury. Chambers finished sixth in the final of the 100m on Sunday night, clocking a season's best of 10.00sec behind Usain Bolt.
The heats of the 200m begin tonight in the Olympiastadion, with Bolt set to go for a second victory. The American Tyson Gay is the defending champion and runner-up in the 100m, but is struggling with a groin injury.
Gay, meanwhile, is to run the 100m at the British Grand Prix in Gateshead on 31 August. Gay's 9.71sec in Berlin was the third-fastest 100 metres time ever.
Jeremy Wariner, meanwhile, said yesterday that he is ready to improve on his silver medal performance at the Beijing Olympics and defend his world title in the 400m. "After the season I had last year, it's really important for me to come here and defend my title," Wariner said. "A lot of people are counting me out, expecting me to take silver. My expectations are to come in here and defend my title the best I can." Wariner, 25, won gold in the 400 at the Athens Olympics in 2004 and the world championships in both 2005 and 2007.