JOIN USJamaican officials confirmed Mullings, the year's third fastest sprinter in the 100M, had been suspended from the team headlined by triple Olympic and world champion Usain Bolt, but declined to elaborate on what grounds.
"Because of the outstanding issue surrounding Mr Mullings he had to be omitted from the team," Jamaica Athletics Administrative Association (JAAA) executive member and treasurer Ludlow Watts told Reuters.
"However, if the matter is resolved in his favour, there is a provision where he (Mullings) can be re-instated at a later date."
JAAA general secretary Garth Gayle added that Mullings had been omitted "because of his suspension."
The Jamaica Anti-Doping Commission (JADCO) last week said a Jamaican track and field athlete had tested positive at national trials for the world championships but did not release a name.
Jamaica athletics sources with knowledge of the issue confirmed to Reuters that Mullings was the athlete who had failed the doping test.
Mullings, a member of Jamaica's gold medal-winning 4x100 metres relay team at the 2009 World Championships in Berlin, was fastest in the 200M and placed third in the 100M at Jamaica's trials in June.
He had been expected to join defending champion Bolt in the 100 and 200M and help Jamaica defend their 4x100M relay title in Daegu.
The team, announced on Monday, did not specify which events Bolt or any of the other athletes would contest at the Aug. 27-Sept 4 championships.
Asafa Powell, the former world record holder and world bronze medallist, was included and should be one of Bolt's biggest challengers in the 100M.
Reigning world champions Shelly-Ann Fraser-Pryce (100M), Brigitte Foster-Hylton (100M hurdles) and Melaine Walker (400M hurdles) were also included in the team along with Olympic 200M champion Veronica Campbell-Brown.
Meanwhile, Bolt arrived in Daegu on Tuesday to prepare for the defence of his world titles.