At Sunday’s Red-Blue Game at McKale Center, the play of junior center Chase Jeter — a hint of what he might be (or not be) — seems to be the most significant development. If Jeter isn’t productive and reliable, Arizona probably won’t be able to break .500 in the Pac-12. Jeter’s two seasons at Duke were not promising: He averaged 1.9 and 2.6 points per game and was not a reliable rebounder. But he’s had a full year to learn Arizona’s system and work on his strength, conditioning and, maybe more importantly, his confidence. The Pac-12 is not a national power, but there are enough reasonably good teams that breaking 9-9 will be difficult for any team except Oregon and UCLA.