Plans were last evening in final stages to fly Bomet Governor Isaac Ruto to South Africa for specialised treatment.
Officials close to him said his doctors had allowed him to travel for the treatment after he hurt his visage.
Last night, the governor tweeted that he was departing for South Africa for further treatment at 8:35pm.
A tear-gas canister that did not explode hurled by a police officer hit him on the face, injuring the bridge of his nose.
Mr Ruto said the canister did not explode and had been hurled at him on Sunday in a clash with the police.
Ruto sustained a cut and was attended at a local hospital and later in Nairobi on Monday before leaving for South Africa.
He said at the airport he was attacked by police who had been instructed by politicians to harm him.
Ruto said he had tried to seek the release of youths arrested at the stadium before it turned chaotic, with police lobbing tear-gas canisters, one of which hit him below his right eye.
The governor was taken to The Nairobi Hospital upon landing at the Wilson Airport at 8am on Monday.
He said he was attending a church service at Njerian AGC, Silibwet Township Ward, when he received text messages of complaints from youths attending a football match at Silibwet stadium.
"The youths complained that they had been arrested by the police while others were being harassed at the stadium," he said.
After the church service, Ruto said he went to the stadium to intervene and on arrival, a huge crowd gathered around him as he approached the police officers.
"A police officer in uniform tried to hit me with a baton but my security thwarted the move and a heated confrontation ensued before around 10 officers retreated and lobbed tear-gas canisters directly at me."
"I have even informed Interior Cabinet Secretary Joseph Nkaissery but nothing seems to be working," he said.