Shettar became chief minister last July and is heading the BJP's third government since it came to power in the state for the first time in May 2008. He also holds finance portfolio.
While Yeddyurappa has turned coy over his next moves, after repeatedly threatening to bring down the Shettar government to prevent the budget presentation, his supporters are flaunting the names of the ministers who will quit Jan 23.
The ministers, C.M. Udasi (public works), Shobha Karandlaje (energy), M.P. Renukacharya (excise) and Murugesh Nirani (industries), are also keeping the Bharatiya Janata Party on tenterhooks by maintaining silence on their plans.
Staunch Yeddyurappa loyalist and BJP legislator Nehru Olekar has been repeating since early this month that over 20 legislators, including four ministers, will quit the assembly Jan 23.
If the resignations come through, the Shettar government will be reduced to a minority as the BJP's numbers will come down from 117 in the 225-member assembly to less than 100.
Of the 225 members, 224 are elected and one is nominated.
The Congress has 71 members and the Janata Dal-Secular (JD-S) 26. There are seven Independents while three seats are vacant.
Yeddyurappa, who quit BJP and the assembly Nov 30 and became president of the Karnataka Janata Party (KJP) Dec 9, is against allowing Shettar to present the budget as that could give advantage to the ruling party in the assembly elections due in May.
The Congress and the JD-S are also opposing Shettar's plan to present a full budget instead of going in for a vote on account - legislative sanction to spend money till elections are held and a new government takes over.
There is no legal bar on governments presenting a full budget even though elections are just months away.
However as a matter of propriety, governments refrain from presenting a full budget and go for a vote on account.
The Congress, the JD-S and Yeddyurappa have all been contending that the Shettar government has in effect lost majority in the assembly and hence has no moral right to present the budget.
Their contention is based on the fact that 15 BJP assembly members have been openly backing Yeddyurappa and his new party since Dec 9.
At least four more assembly members have also been openly associating with the another party founded by B. Sriramulu, a former BJP minister and follower of former BJP minister and jailed mining baron G. Janardhana Reddy.
Shettar and the BJP have taken the stand that since none of these 20-odd party legislators has quit the assembly so far, they are still members of the ruling party.
The BJP has also not taken any action against the rebel legislators in order to ensure survival of the Shettar government till elections.
Shettar is confident that not many party legislators will quit and he will present the budget.
To show it is business as usual for his government, he held talks Monday with state industrialists on their wish list from the budget.
Karnataka budget day fixed, BJP waits for Yeddyurappa to strike