What is a “sleeper”?
In the prospect game, the concept of sleepers and breakouts is used to identify players who are off the radar. So much attention is paid to prospect rankings, which center around the top ten prospects in any system. This leaves a lot of potential MLB players out of the mix. Even with a top 30 ranking, there are going to be future MLB players who are left out.
A sleeper can be someone who everyone else is sleeping on as a potential MLB player. It can also be a player with the talent to be a top prospect, who is currently sleeping in terms of his production.