Rockies' Nolan Arenado slipping on top prospect lists, but why?

Last week, during MLB Network's unveiling of Jonathan Mayo's Top 50 Prospects list, I sat in awe as no Colorado Rockies players -- particularly, 2011 Arizona Fall League darling Nolan Arenado -- were mentioned as the countdown reached 40, then 30, then 20. Soon enough, the network's commentators went through the entire list without including a single purple-clad prospect.

More: Rockies' top 10 prospects | 2012 in review | Pebble Report archive

If I was shocked at Mayo's list, imagine the utter dismay I felt upon reading Keith Law's Top 100 list, which was posted Tuesday on ESPN.com. While Law did manage to include two Rockies farmhands, David Dahl at No. 37 and Trevor Story at No. 85, the former Toronto Blue Jays executive failed to place Arenado on that list as well as his list of 10 players who just missed the cut.

That begs the question: Did Arenado really perform that poorly in 2012, or was he saddled with unrealistic expectations? And, how concerned should we be about Arenado's perceived makeup issues that surfaced last season?

Law's explanation for omitting Arenado was that he "had no real case" to be on the list because "he wasn't good in AA." However, with park factors taken into account, Arenado actually performed better in 2012 than he did in 2011, when he hit .298/.349/.487 and drove in 122 runs for High-A Modesto. After a somewhat-disappointing start as a 21-year-old at Double-A Tulsa, Arenado turned it on down the stretch, hitting .350 with five home runs and 17 runs batted in from Aug. 1 through the end of the season. All of that resulted in a 110 wRC+ for the season, two points better than the 108 mark he posted in 2011.

Sure, Arenado benefited from a more aggressive approach at the plate late in the season; he drew just six walks in August and September, good for a 3.8 percent walk rate, down from 7.8 percent in April through July. However, he also seemed to simply snap out of a pouting-laced mental funk which, according to some, was the result of not being called up to the big club in June.

So, how much should we worry about that going forward? Well, two Rockies beat reporters seem to think that Arenado's moping issues are behind him. Tracy Ringolsby told me that Arenado "provided a very positive answer to what was his first pro ball adversity," and also believes that too much is being made of the situation.

Meanwhile, Troy Renck came away from conversations with both Arenado and Bill Geivett with the impression that the young third baseman learned a lot from, and was "humbled" by, his struggles a year ago. Renck added that Arenado seems "driven" headed into spring training.

Whether or not Arenado starts the season in the big leagues is "up to him," says Ringolsby. Talk of Arenado reaching the majors out of spring training last season may have been unrealistic in hindsight, but it is certainly a plausible scenario this time around if he's willing to fight for it.