Tusker says coach Robert Matano is in stable condition at Nairobi West Hospital where he is receiving treatment.
Matano, 56, was admitted at the health facility on Saturday after being taken ill.
The club's chairman, Dan Aduda, told Nation Sport on Sunday that not all results for the tests done to establish what is ailing the veteran tactician are out.
"I talked to the doctor and he told me that he (Matano) is stable. The doctor is waiting for results of part of the tests that were carried out," said Aduda, without revealing the outcome of the tests citing confidentiality.
He added: "We are monitoring his progress and hopes he recovers soon."
Matano, who is the chairman of the Kenya Football Coaches Association, is a two-time Premier League winner with Sofapaka (2009) and Tusker (2012).
He is a former AFC Leopards player and coach, and has also been in charge of various grassroots football clubs in the country.
In last season's competition which ended prematurely due to Covid-19, Matano guided the Brewers to second place on 34 points, five behind winners Gor Mahia.
His admission to the hospital on Saturday happened barely a day after former Tusker and Harambee Stars coach Jacob "Ghost " Mulee was discharged from Aga Khan Hospital in Nairobi, where he had been rushed to, after being involved in a road accident on Friday morning.
"I've done tests after today's accident and I've been cleared by the doctors at Aga Khan Hospital. I take this opportunity to thank everyone who wished me a quick recovery. God is good all the time," Mulee tweeted on Friday.