Ted Cruz's campaign concedes that next Tuesday's primaries in Pennsylvania, Connecticut, Delaware, Rhode Island, and Maryland will be difficult for Cruz, and on late Sunday afternoon campaign chairman Chad Sweet admitted that the biggest prize of the day, Pennsylvania, "will likely go mostly for Trump."

The best hope for Cruz, Sweet told members of Cruz's national security team in an on-the-record conference call, is to win a "fair share" of the delegates at stake in the Keystone State.

"We knew all along ... that this particular stretch of states in the Northeast was going to be probably the low point of the campaign in terms of our ability to win delegates," Sweet said, noting Cruz's loss last week in New York. "We recognize it's going to be a tough stretch for us on Tuesday. We always anticipated that we would have to ride through that period, and fortunately for us, a number of the key states, including Pennsylvania, which will be one of the big states on Tuesday that will likely go mostly for Trump, we'll still win a fair share, Kasich will still win a fair share. If you combine both Kasich and us together, you'll see that the anti-Trump vote exceeds the Trump vote."

Donald Trump leads Cruz by 19.5 points in the RealClearPolitics average of polls in Pennsylvania. Under the state's complex delegate allocation system, 17 delegates will go to the statewide winner, while 54 more delegates will be unbound to any candidate, even on the first ballot. Many delegate candidates have said they intend to support whoever wins their district or the state.

Things will look up for Cruz when the campaign moves to "very favorable territory" in the Midwest and beyond, Sweet said. But Sweet did not predict victory in Indiana, a state that is shaping up as critical in Cruz's effort to keep Trump from winning the 1,237 delegates required to win the Republican nomination on the first ballot.

"We will likely outperform expectations in Indiana," Sweet told the group. "We feel very good about where we are in Nebraska, Montana, and as you look towards the far west, into Washington, Oregon, and California..."

Trump leads Cruz by 6.3 points in the RealClearPolitics average of polls in Indiana, which holds its primary May 3.

Sweet emphasized that Cruz is still beating Trump soundly in the work of winning the loyalty of delegates at local conventions across the country. "On the ground game, that is where we continue to outperform Trump ... even with the arrival of Paul Manafort," Sweet said. Still, Sweet added, Cruz cannot assume that advantage will last. "We should not take that for granted," Sweet told the group. "At some point, they will get their act together on the ground game, and we have to be ready for that."