text: A Bhuvneshwar Kumar throw hit Reiffel on the back of the head on day one and he was replaced by Marais Erasmus.
  Scans gave the Australian the all clear but he has been advised to rest.
  Erasmus will continue alongside Bruce Oxenford on the field for the rest of the match, while Chettithody Shamshuddin takes over as third umpire.
  "Paul Reiffel underwent precautionary tests yesterday (Thursday), which came back all clear," said an International Cricket Council statement.
  "Paul, however, has been advised to rest - which is the normal course prescribed following a concussion.
  "As such, he will not take any further part in the Mumbai Test and has been replaced by Marais Erasmus."
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target: Umpire Paul Reiffel has been replaced for England's fourth Test in India as he recovers from concussion after being hit on head by a stray throw.