The Congress party source dismissed speculation that Mukherjee would be a "caretaker PM," which would require him to take "an oath."
Dr Singh will be admitted to AIIMS before 1500 hours on Friday. The prime minister will undergo by-pass surgery on Saturday.
A team of doctors, who examined Dr Singh on Friday morning, discovered that he is experiencing some uneasiness, hence the decision to admit him to hospital on Friday afternoon.
The PM would be undergoing a coronary artery bypass graft surgery on January 24, 2009 at AIIMS, New Delhi. The surgery would be performed by a team of doctors drawn from AIIMS and the Asian Heart Institute, Mumbai. They would be supported by a team of doctors and technical staff drawn from other departments of AIIMS.The surgical team from AHI will include Rama Kant Panda, cardiac surgeon, Vijay Desilva, ICU specialist, and Narendra Garach, anesthetist, hospital sources said.
A source, who is familiar with Dr Singh's condition, told rediff.com "The PM is fine and there is nothing to worry these days, when by-pass surgery does not pose any serious risk."
Dr Singh will require about a week to recover from post-surgery treatment, a medical expert said; it will take him a fortnight to resume his normal routine.
"All sensitive decisions about matters of governance will be surely taken only in consultation with the PM," a highly reliable Congress source added.
"Only if the PM decides will an alternative be taken up," he said, "Right now, his health is functional. We don't see any need to ponder further on the issue."
The Prime Minister will miss the Republic Day parade. External Affairs Minister Pranab Mukherjee would be laying the wreath at the Amar Jawan Jyoti on that day.
Singh had undergone a coronary artery by-pass surgery in the UK in 1990 and angioplasty a few years ago.
Additional Inputs: PTI
