A top aide to Trump told NBC News that the team is pursuing a two-pronged strategy to make sure he gets the 1,237 delegates he needs to proceed to the November general election.
Barry Bennett, a former adviser to GOP presidential candidate Ben Carson, told NBC the Trump campaign is courting "tons" of delegates in preparation for the "open" or "contested" convention Republicans will hold if no candidate reaches the 1,237 threshold outright.
"You've got 40 days between the last primary and the convention to go woo the appropriate number of unbound delegates," he told NBC.
At an open convention, delegates on the floor vote in rounds until they settle on a nominee.
NBC noted "there are now 323 delegates currently up for grabs on the first ballot. These are delegates who backed Rubio and Carson or hail from states that don't bind their vote, (such as Colorado and North Dakota)."
If Trump — who has said he thinks there would be "riots" if he doesn't get the nomination — can get signed pledges from enough of those uncommitted delegates, it would send the entire party a sign that he's got the nomination locked up.
There are still many states that haven't yet voted, and Trump, as he's said, could win enough delegates in those primaries to secure the nomination outright.
The next big contest comes April 5 in Wisconsin, followed by the New York GOP primary April 19.