TORONTO - Byelections can be game changers, pivotal moments when the fate of a government is largely foretold by outrage at the ballot box.

Just don't expect that to happen in Thursday's votes, experts say.

The two byelections in eastern Ontario likely won't change the makeup of the legislature or send a message of protest to Premier Dalton McGuinty, said Bryan Evans, a politics professor at Toronto's Ryerson University.

"I think that the big story is that there's no story here," he said.

"I'm not going to really go out on a limb, but I don't think there will be any change."

He said he'd be "shocked" if the rural riding of Leeds-Grenville, which has flown Tory blue for nearly three decades, switches sides. And the Liberals will likely hang on to the suburban riding of Ottawa-West Nepean, given the party's star candidate Bob Chiarelli is an ex-Ottawa mayor who'd previously held the riding for 10 years.

Despite the "plethora of issues" that voters could protest - from tax harmonization to cash-strapped hospitals - the Liberals have had "phenomenal success" in byelections, Evans said.

Since the 2007 provincial election, the governing Liberals have held on to two seats in downtown Toronto and nabbed another from the Tories in the central Ontario riding of Haliburton-Kawartha Lakes-Brock, he added.

"There's certainly no indication that there's an upswell or coalescing of public opinion around issues which the opposition parties have thrown up," he said.

Chiarelli, who's widely expected to be on the fast-track to cabinet if he reclaims the Ottawa seat he relinquished in 1997, said voters are more concerned about health care and education than tax harmonization.

"The main message I'm getting is that they don't want their services impacted or cut. In fact, they want to see increases in services, whether it's education or health care - the two major ones."

Still, the Conservatives and NDP insist there's no shortage of voter anger about the HST.

"We're getting it at the door, almost every door," said former Brockville mayor Steve Clark, who hopes to hold on the Leed-Grenville seat for the Tories.

"It's been a concern from everyone, whether they'd be a senior, or they'd be a small business owner, whether they'd be a working family. ... People are extremely upset that this tax is going ahead given the economy."

If the Liberals hang on to the Ottawa seat, they may take it as a sign that the HST and the spending scandals at eHealth and the troubled Ontario Lottery and Gaming Corp. aren't as toxic as they feared, Evans said.

"Clearly the electorate aren't motivated to punish the government over those issues. For whatever reason, those issues don't resonate to such a degree that people feel there's a need to send a message."

McGuinty isn't saying what a victory would signal to him, but noted that he's not met a parent or grandparent who isn't in favour of the jobs the HST would create in the province.

"We spend a lot of time talking about the HST, but the experience has been at the doors that the voters actually carefully consider a number of factors when it comes to making a decision," he said Tuesday.

All three parties have also squared off on health care during the campaign period, with hospital cuts coming up almost daily in the legislature.

The New Democrats hammered the Liberals on the threatened closure of the Toronto Grace hospital in the February byelection, which saw them zoom past the Tories to finish second in the Toronto-Centre race.

On the eve of the vote, the government promised an estimated $15 million to keep the hospital open and the Liberals ended up hanging onto the seat.

A week later, Finance Minister Dwight Duncan promised to provide about $200 million to help Nortel pensioners, many of whom live in Ottawa, after Chiarelli urged the government to help them.

Opposition critics accused McGuinty of trying to buy another byelection on the backs of seniors, but the premier brushed off suggestions that his timing was suspicious.

The writs in eastern Ontario were dropped after former Liberal cabinet minister Jim Watson vacated his suburban Ottawa seat to run for mayor, and veteran Conservative Bob Runciman stepped down in Leeds-Grenville after 29 years to take a Senate appointment.

Clark, 49, will face off against Liberal Stephen Mazurek, New Democrat Steve Armstrong and the Green Party's Neil Kudrinko in Leeds-Grenville.

In Ottawa West-Nepean, Chiarelli, 68, will face off against Beth Graham, a 55-year-old former aide to both federal Health Minister Leona Aglukkaq and provincial Tory Lisa McLeod. School trustee Pam FitzGerald will represent the New Democrats and Mark MacKenzie is on the ballot for the Green Party.

Chiarelli, a father of six who represented the riding from 1987 to 1997 before his two terms as the first mayor of the amalgamated city of Ottawa, said he had been mulling a political comeback long before Watson resigned, and even considered taking another shot at the mayor's office.