After posting my top 5 Yankees pitching prospects at The Baseball Think Factory, one individual commented that there was no mention of Mark Melancon who they thought was much more talented than David Robertson. So, without spending too much time on this, here are both pitchers stats as well as Jonathan Papelbon and Huston Street's stats.
Unfortunately for the sake of this comparison, Street only pitched 10 innings at A ball before being called up to pitch for the A's. But I think we have enough information here to see that not only is Robertson more talented than Melancon, there really isn't much of a comparison at all that suggests that they're even close.
If anyone is interested, here's how Robertson and Street match up as far as their MLB stats for 2008.
The sample size for Robertson is only 16 innings, but I think his stats are about where they should be. His walk rate is a little bit inflated, but as a rookie it's not surprising. Street's strike out rate is a bit down from last year, but seems in line with previous stats. The same goes for his walk rate and ground ball rate. If I was a betting man, I'd put my money on Robertson to be the better reliever in a couple of years, but that's just my opinion.
Edit: Melancon underwent Tommy John Surgery in 2006, so it could be argued that he has not fully recovered and his current stats don't reflect his true potential. However, he would have to increase his strikeout rates by 50% in order to compare well with Robertson, and I don't see that happening. A 25% increase may be possible, but 50% is unreasonable.