If John Kasich were not still (pointlessly) in the race, Ted Cruz would likely walk away with all 98 delegates that will be awarded today. Based on the polling and the way that Ted Cruz has closed races lately, if he loses in winner-take-all Arizona, it will be close. Probably the margin will be way less than whatever John Kasich brings in.
Likewise in Utah, the polling indicates that Utah voters really dislike Donald Trump, and that Cruz is at or near the 50% threshold to take all the delegates from Utah. If not for Kasich's presence in the race, Cruz would almost definitely walk away with all 40 of the delegates from Utah.
Even in this scenario, Ted Cruz would still face a very difficult uphill climb to reach 1,237 himself. However, the chances for a contested convention would be astronomically improved.
Instead, thanks to John Kasich, Donald Trump might well win some portion of the 98 delegates at issue today and move himself closer to the 1,237 mark, so that he will not have to face a contested convention.
Kasich likes to blithely assert that no candidate is going to get to 1,237 before the convention no matter what, but he's shown absolutely no reason why that might be so. Trump still has California and New York in his future which means that Cruz and Kasich will have to scrape every delegate out of Trump's stubby hands that they possibly can.
Kasich's continued presence in this race dangerously elevates the possibility that Trump will be the nominee outright, in exchange for the incredibly small benefit to Kasich that he has an outside chance in hell of being chosen at a contested convention.
John Kasich is playing chicken with the future of this country for his own doomed and quixotic quest. Maybe the guy who bills himself as having some political smarts can read the writing on the wall and get out of this contest before calamity strikes.