This is an interesting one, because I'm not sure how it was really meant. I'll post it as I see it.
In 2013-14 I was buying a lot of cards at retail. My second year back into the NBA, I was collecting heavily at that time- more than I am now in fact.
Panini makes very small sets. Most are 200 cards. It's not hard to get at least one card of a person if they are one of the "chosen ones" Panini puts into sets. (With a 450 man league, Panini usually ignores more than half of it).
With the way Panini does things, there are a core group of rookies that they put in every set, and then some other rookies who show up in some sets. Ray McCallum was one of the original group of rookies who was in every set.
Despite my opening a ton of packs that year, I did not get a single McCallum card. He was the only main rookie of the season I did not add to my collection during that season.
Eventually, I've gotten a couple of cards of him. Not many, but he has been rare to see in a set post-rookie season.
In a bit of a humorous twist, I recently found a pack of 2013-14 Hoops that I had gotten in a blaster when the set was new, but I had misplaced it. I opened it up and what do I find?
Funny how that works some times.