Since Ben Stokes clinched the famous win nine days ago, James Anderson has been ruled out of the tour with a rib injury and Jack Leach has returned home because of illness.
Mark Wood has been named in England's team for the third Test against South Africa, with Jofra Archer still unable to return to the side.
England wicketkeeper Buttler was disciplined by the International Cricket Council for an expletive-laden outburst at Vernon Philander during the tourists day five victory in Cape Town, earning one demerit point and losing 15 per cent of his match fee.
It means a potential opening for Wood or Archer - both of whom are capable of frequently topping 90 miles per hour - providing their own injury complaints are in order.
Root said fellow fast bowler Jofra Archer still felt some soreness from the elbow injury which kept him out of the second Test.
"That decision hasn't been made", Root told a news conference, with regards to Anderson's replacement. We'll find out who they go with at the toss shortly. He's going to work extremely hard to try and get himself fit again.
Chris Woakes represents an alternative if England opt not to chance Archer or Wood, but there is no doubt selecting either of the speed merchants carries added allure.
He hasn't played in a red-ball match since a Test series in the West Indies last February.
"Credit to Woody, he's worked extremely hard as well. It is clear to see what he is capable of doing", Root said.
"If he is 100% and firing, the skills he has at his pace will be a great asset in Test cricket".
Wood is the only change for England, who will bat first in Port Elizabeth after winning the toss. 'It's not really something you can say on a stump mic.
"The way he has performed across all the formats has been fantastic".