The first GOP debate field of 2016 is set - and 2 major candidates are out

The next time that the Republican presidential candidates take the stage for a prime-time debate, several notable candidates will be missing. 

On Monday evening, Fox Business, which will host the Republican debate on Thursday, released the names of candidates who qualified for the main-stage debate.

Here's who made the cut:

Front-runner Donald Trump, Sen. Ted Cruz (R-Texas), Sen. Marco Rubio (R-Florida), retired neurosurgeon Ben Carson, New Jersey Gov. Chris Christie (R), former Florida Gov. Jeb Bush (R), Ohio Gov. John Kasich (R), and former Florida Gov. Jeb Bush (R).

Notably, former Hewlett-Packard CEO Carly Fiorina and Sen. Rand Paul (R-Kentucky) failed to qualify. They will have the option to join former Arkansas Gov. Mike Huckabee (R) and former Sen. Rick Santorum (R-Pennsylvania) on the early debate stage, where both have been relegated for the last several debates. 

Paul reportedly slammed the decision, telling CNN that Fox Business was making a "mistake" by not including him in the upcoming debate.

Last month, Fox Business tightened the debate criteria, requiring that candidates meet slightly higher guidelines in order to qualify. The network required presidential candidates to place in fifth in averages of the five most recent reputable Iowa or New Hampshire state polls, or in sixth in averages of recent reputable national polls. 

Both Paul and Fiorina's campaigns noted on Monday that some surveys showed the candidates in fifth and sixth place.

Fiorina's campaign manager noted that Fiorina would qualify if Fox Business relied on Fox News' own national polls.

It's unclear whether the demotion to the undercard stage will encourage Paul to think more seriously about turning his attention to his Senate campaign in Kentucky, where he's simultaneously running for reelection. 

Paul's campaign did not respond to Business Insider's request for comment.