When you hear that a prospect has been demoted, it usually brings about a negative connotation. Players are always supposed to be moving forward, so when they start moving back, there can be some thought that things aren't working out.
It's similar to you or me starting a new office job, doing so well that we force a promotion from the bosses, then struggling to adapt to the new surroundings and responsibilities that we get pushed down the ladder.
But not every demotion is a bad thing. Some teams play hard and fast with prospects, especially those loaded with tools, bumping them up a level or two before they are capable of handling it.
A great recent example of an aggressive promotion that didn't work was Rymer Liriano of the San Diego Padres. He has four above-average or better raw tools (power, speed, arm strength, glove) and was pushed to High-A as a 19-year-old in 2010.
Liriano struggled, hitting .220/.291/.320 in 14 games, prompting the Padres to push him back to Low-A in 2011. He found his groove as a prospect after the demotion, hitting .319/.383/.499 with 12 home runs and 65 stolen bases in 116 games.
Unsurprisingly, Liriano's prospect status soared as he put all his tools on display in a league that he had already played the previous year (and was still very young to be there when he repeated it).
The 2013 season is still very young, so the odds of a team throwing up their hands and demoting a prospect now is highly unlikely—and unwarranted. But we will talk about some players who need to turn things around, or run the risk of being sent down a level to fix a few things.
Note: All stats courtesy of MiLB.com unless otherwise noted.