The news followed hours of reports that the presumptive Republican nominee had chose to pick Indiana Governor Mike Pence, and pushback from the campaign saying no decision had yet been made.
Consideration of Pence also has put Trump on the clock.
Republican presidential hopeful Donald Trump postponed announcing his pick for running mate, which had been scheduled for Friday, July 15, following an attack in Nice that has left some 70 people dead.
In addition to testing the men's chemistry together, Trump was reportedly impressed with Pence's calm demeanor, his experience on Capitol Hill and as a governor, and Pence's potential to assist Trump in governing, should the ticket win in November.
Pence emerged relatively late in the vice presidential stakes. And it appeared to end Pence's 2016 presidential aspirations.
Gingrich told The Associated Press he was expecting to hear from Trump one way or the other sometime after 1 p.m. The former Georgia congressman praised Trump for running a "very fair, open process" and said he looked forward to learning the businessman's decision.
It "will focus on the core themes of Republican Presidential Nominee Donald J. Trump's campaign: national security, immigration, trade and jobs".
Mr Pence, a staunch conservative who served six terms in Congress, is seen as a running mate who would have the backing of party leaders and ease some of their concerns about Mr Trump's political inexperience and volatile temperament. Critics said it could have opened the door for companies to discriminate on the grounds of sexual orientation.
After many protests and the NCAA, which is headquartered in IN, warned such a law could cost the state the chance to host sports events, Pence signed a modified version of the bill. We have to get awfully tough and we have to get very, very smart and vigilant and if we don't, we're just not going to have a society, we're not going to have a world anymore.
Authorities found weapons and grenades in the truck, regional president Christian Estrosi told BFM TV.
According to Trump, Hillary Clinton is "weak and ineffective".
"I have great respect for the governor of IN", said Rudy Fernandez, a White House adviser to former President George W. Bush. But the final decision rests with the candidate, who is known for making decisions more on instinct than other factors - and for sometimes changing his mind.
"In Trump, you have one of the most divisive and offensive candidates to Hispanics in recent memory", Fernandez said.
"Mike Pence appointed me to serve on the board of directors for House conservatives, and I attended his inauguration in IN", said U.S. Rep. Kevin Brady, R-The Woodlands.