"I think the defensive aspect of the college game caused me to not be able to play a lot," York said.
"I got a little bit of a taste of college basketball, and knowing that I wanted to play but not really getting that opportunity, it was time for me to change something."
York spent nearly his entire summer in the gym, working on all aspects of his game.
While he continued to refine his jump shot that earned him high praise on the recruiting trail, the 6-foot-2 sharpshooter knows it will be his defense that determines how many minutes he plays each night.
With a lack of proven shooters on the roster, York could create a niche for himself in Arizona's rotation if he's able to carry over the gains he made during the offseason. He hit 35 percent of his three-point attempts in limited duty last year.
"His defense has really, really gotten a lot better," Brandon Ashley said of York. "We all know he's a great scorer and we saw him do it in spurts last year, so his defense was really one of his main focuses this off-season and he really improved on that a great deal."
There will be no shortage of competition for playing time in practice. York realizes he has two upperclassmen ahead of him in T.J. McConnell and Nick Johnson, and also has senior guard Jordin Mayes vying for minutes.
Sean Miller admitted in a recent press conference that outside shooting was one of the bigger questions facing the team this season.
The Wildcats could be challenged early with zone defenses instead of typical man-to-man play, which will force UA to hit outside shots.
If York is able to get on the floor, he could be an x-factor for a team with Final Four aspirations.
"Going through what I went through last year during the season has definitely helped me during the off-season to become a better basketball player both on and off the court, offensively and defensively," York said.