London - The South African athletics team manager Hezekiel Sepeng defended their surprise decision to drop LJ van Zyl for the preliminary round of the men's 4x400m.
Van Zyl was one of the quartet of Shane Victor, Ofentse Mogawane and Willem de Beer, which finished second at the final of last year's World Championships in Daegu.
His lack of form in his specialist event, the 400m hurdles, has apparently been the reason for his exclusion from the team.
"He's not dropped from the team, we will be using the other four guys for our preliminary rounds," Sepeng said.
"We will finalise the team after the guys have qualified and see how everybody looks, but for the heats we don't want to push LJ because he just finished racing."
The team for Thursday's heats will be Oscar Pistorius, Mogowane, De Beer and Shaun de Jager.
Van Zyl, who last year ran a personal best of 44.86 second has experienced a serious drop in form.
His best flat time this year is 46.51, which he ran in Potchefstroom in March.
The SA record holder in the 400m hurdles took a further knock to his confidence when he crashed out of the heats of the one-lap hurdles at the Games last Friday.
He looked out of sorts in his specialist event finishing sixth in a time of 50.31.
"We've got six athletes for the relay. LJ and Cornel Fredericks did the hurdles, Fredericks is injured so he is automatically ruled out," Sepeng said.
"LJ wasn't feeling good and he didn't run a good race.
"That means we are left with the four guys, so we don't have a choice."
Sepeng said he and the athletics coaches felt it was the best team to take them through to the final of the relay.
"For us it is a decision that we need to take, we can't take chances we need to make that final," he said.
"Oscar is doing really well at the moment and the other guys, the training that they did shows that they are ready."
The double amputee sprinter made history at the World Championships when he earned a medal for his contribution in the preliminary rounds.
Pistorius, Victor, Mogawane and De Beer progressed to the final in style when they set a new national record of 2:59.21.
Pistorius made history again last Saturday when he became the first amputee to participate in a track event at the Games.
He came second in his heat with a time of 45.44 but failed to progress past the semi-finals when he finished last in his semi-final with a time of 46.54.