Top 20 impact prospects for 2012

This is the second edition of this re-ranking of top prospects just based on their potential impact in the coming year, a list that is based as much on expectations of playing time as it is on projection of their abilities. Unlike last year, we don't have that many rookies likely to win significant roles right out of spring training -- two position players, five starting pitchers and two relievers, by my rough count. But there are a number of impact prospects likely to get the call in June or July and produce real value in the majors, as we saw last year from Brett Lawrie, Desmond Jennings and Dustin Ackley. Here are the top 20 such players, with a few honorable mentions whose playing time in 2012 is less certain.

1. Matt Moore, LHP | Top 100 rank -- 3: If you saw him last year, you know he's ready. He'll miss bats, throw strikes and will only be held back by the way the Rays manage his workload to keep him healthy for the long haul. If he gets the innings, he should finish in the top 10 in the American League in strikeouts.