In the vernacular of sports, "breakout" is a nebulous term. It means different things to different people.
Here's what it means to me: a not-yet-star player who elevates his game and statistics significantly. He can be a youngster who's only sipped his cup of coffee or have a few seasons under his belt. He can trail some hype or toil in relative obscurity.
In fact, you'll find guys who match all of those descriptions here. There are top prospects with rookie status intact about to get their first extended shot, established players coming back from injuries and a few names who have taxied down the runway of stardom and appear poised for liftoff.