But ultimately, I don’t see the quarterback competition being decided by which quarterback has the higher passing rating in training camp. So to some degree a close accounting of passing stats for each quarterback may be focusing on the wrong thing.
Instead, I suspect the competition will be decided by which quarterback grows into being able to run the full offense, from getting the plays called on time, to getting to the right play at the line of scrimmage, to being able to aggressively take what the defense gives him. For Kyler Murray, that means mostly continuing to gain familiarity and comfort with the offense and personnel and eliminating mistakes along the way. For J.J. McCarthy, that means mostly growing his skillset to be better able to aggressively take what the defense gives him.
In a short competition, whether it lasts for a week or a month from now, that favors the more experienced Murray, who should be able to slowly become more versed in the scheme and in tune with receivers. It may be more difficult for McCarthy, who has said he has improved dramatically from last season, to show more touch, layering ability, and accuracy with his throws while also being able to process faster.
But over the next year, McCarthy may be able to get there. In the meantime, he needs to get out of his comfort zone and challenge himself and test his limits. That means trusting what he sees and attempting more difficult throws when available. That probably means making more mistakes too, but that is what training camp is for.
For Murray, moving to a new team and scheme forces him out of his comfort zone and so the challenge for him is to grow into the new system and slowly begin to master it. That may also lead to working on some aspect(s) of how he approaches the game as well. A change of scenery can also have the benefit of a better team around him and a more positive atmosphere and a chance to change some narratives about him.
So, at the end of the day, the competition may be decided not by who did the best from beginning to end, but by who progressed/improved the most with their to-do list. I would imagine that over the next week to ten days the coaching staff will have a good idea about the rate of progress for each quarterback and may be ready to make a decision on who is the starter.