Former Republican presidential nominee Mitt Romney will give a speech on Thursday addressing his party's presidential race, according to online reports

The 2012 nominee and former Massachusetts governor will address the Hinckley Institute of Politics at the University of Utah.

Romney's involvement in the race so far has been limited to lashing out at GOP front-runnerover his harsh rhetoric and refusal to release tax returns.

Romney last week warned of a "bombshell" in Trump's tax returns in a Fox News interview.

“Either he’s not anywhere near as wealthy as he says he is, or he hasn’t been paying the kind of taxes we would expect him to pay, or perhaps he hasn’t been giving money to the vets or the disabled like he’s been telling us he’s been doing.”

Speculation had been mounting as to whether Romney will endorse a candidate, or even enter the race himself in an effort to counter Trump's surging campaign.

But a Romney aide told NBC News that the the speech on Thursday will not be an endorsement or a campaign announcement, though it will still "be worth covering."

And Bloomberg Politics reported that Romney will be laying out the case against Trump, in the wake of the real estate mogul’s strong showing on Super Tuesday. "Mitt doesn't believe Donald Trump is the right person to lead the party," an unnamed source told Bloomberg. "There are a number of mainstream Republicans falling in line with Trump, and he wants to speak up before more people go that route."

Former Romney campaign strategist Katie Packer said in an interview with CNN on Wednesday that she also doesn't believe that he intends to jump into the race. "I don't anticipate that," she said when asked whether Romney was going to leave the door open for a possible candidacy. "I think he's made it very clear that he has no intention of running again, but I do think that he wants to sort of continue to be a voice, an adult in the room if you will, that's just sort of reminding these candidates that that this is a very big office and that the rhetoric should sort of match the importance of the office that these candidates seek. And I think that he's hoping to do that tomorrow." Republican donors and operatives have recently begun efforts to go after him head-on. Our Principles PAC, a group almost singlehandedly funded by billionaire Marlene Ricketts and founded by Packer, has launched an ad campaign against Trump. The ads him for hiring undocumented workers and his history of contradictory statements. The speech comes after Trump has already won 10 of the 15 states that have cast their votes in the primary so far.

- Updated at 3:02 p.m.