Yahoo Sports senior writer Jay Busbee previews this week's second major of the golf season - where this year's Masters champion continues his quest for the calendar grand slam and Spieth looks to match McIlroy with the career version of his own.

As we saw by Rory McIlroy's emotional reaction to winning the Masters and completing the career Grand Slam, the guy was under an insane amount of pressure to finally get the job done. McIlroy admitted he felt "pure relief" after winning the playoff against Justin Rose to make (more) golf history.

McIlroy completed the career Grand Slam at the Masters. Spieth can do the same next week at the PGA Championship—but it won't be easy.