SA's Elgar suffers concussion after nasty blow

South African batsman Dean Elgar was diagnosed with concussion after suffering a wincing blow to the helmet during the third test against India on Monday.

Theunis de Bruyn came in under the new concussion sub rule after opener Elgar took a nasty hit on the helmet from a short Yadav delivery and had to retire hurt on 16.

The impact left the opener shaken as he lay on the ground getting physio assistance.

South Africa said late on Monday that Elgar was "assessed by the team's medical staff and diagnosed with concussion".

"The opening batsman will be closely monitored over the next 24 hours, followed by reassessment every 24 hours until signs and symptoms resolve," the team said in a statement, adding the soonest he can return to play is in six days' time according to concussion protocols.