Morkel forced to return home with hamstring injury
Morkel, who was signed until June 1 as a short-term fill-in for Rana Naved-ul-Hasan, broke down during last week's Championship match against Nottinghamshire. He was diagnosed as having a grade 2 hamstring tear which usually takes between three and six weeks to heal.
"I am really upset that an injury is forcing me to return home," Morkel said. "Everyone at Yorkshire has made me very welcome and I was desperate to take some wickets and get Yorkshire off to the best possible start."
"We are all sad to see Morne depart so soon after his arrival," Martyn Moxon, the county's director of cricket, said. "He was fitting in well, provided our bowling attack with some variety as he is a genuinely quick bowler.
"We have a strong squad and as Rana Naved will be unable to be registered as a Yorkshire player before May 19, there is now a chance for one of our other seamers to grab an unexpected first-team opportunity."
Morkel will travel with the squad for their Friends Provident Trophy match against Lancashire on Sunday before flying back home. He should be fit again in time to return to England with the South African squad at the end of June.