From your link:
” Cruz allies and people close to the campaign describe a budding sense of gloom, with internal polls diving as Trump mounted even stronger than expected showings in his native northeast. In Indiana, which Cruz backers once believed they were favored to win after his strong defeat of Trump in Wisconsin, Cruz’s numbers have fallen precipitously: Once leading, Cruz now trails in the state by eight to 10 points, according to a person who has seen the numbers, with Trump over the 40% mark. Cruz’s campaign did not respond when asked about those figures.
It seems strange that in a state that is being called the Alamo by Cruz people that the polling data seems so sparse. I think that the acts of desperation by Cruz signal that the internal numbers are better for Trump than what is being shown in the public polls. Trump is may be perfectly happy to not publicize their internals to maintain a sense of urgency.