Mke Newman has a nice article about age vs. level when evaluating prospects. He has this great tidbit:
"For me, projecting based on a basic 22-24-26 rule helps keep it simple when at the ballpark scouting. If I can project a player to establish himself for good at 22, then the potential is there for him to be a star. At 24, a player is likely to be a solid regular, but will fall short of star-level status. At 26, a bench role is the most likely outcome. This is not to say it’s a perfect system, as players will occasionally buck the general trend, but I’ve found it serves me quite well in practice"
Gary Brown is 23 in 2012. He's already missed the "rule of thumb" for a star. I think we really need to be rooting for a promotion to AAA mid-season, so he's ready to join the club in 2013. That would at least put him into the "solid regular" bin.
Of course, we could also hope that Gary's an exception to the rule and is just a late bloomer due to his college draft status.
For those who follow Tangotiger, mgl, and inside the book, there's a discussion there, too: