Alonso is not a good LF. He's not even a poor LF-- he's worse than that.
IF (notice the capitals) he can be even poor, he'll be a decent option for a few years.
Cozart, meanwhile, has defensive value even if he pulls a Janish. Which is not likely, as he has enough power to make pitchers pitch to him.
Tough call, IMO.
"You can learn little from victory. You can learn everything from defeat."
-- Christy Matthewson
"Show me a good loser and I'll show you an idiot."
-- Leo Durocher
And to be honest, if you think Alonso is going to have the better career, you should have selected him. That is the definition of prospect, what something will do in the future.
I'm going with Grandal. To me the debate is not settled between him and Mesoraco. I have him rated highest offensively, although I recognize the league he's in elevates that a lot. Nevertheless, he had an impressive year, albeit in the shadow of Mez. .401 OBP, switch hitting Catcher, the power is there, defense is good and should improve with some more reps.
As were Mez's at some point.
Mes for me.
I certainly don't have the access to info that you do. However, when there are mixed reviews on defense, it certainly bears patience. It was Grandal's first full year and he moved quickly up the ranks. I think with more coaching in AAA for the next 2 years, he will become very good on defense. In Bakersfield, there were 128 wild pitches, which led the league, so I do not think that was Grandal's fault, or we'd be hearing now about a switch to another position. The staff was very wild.
In general, I like the polish that he's shown at the plate and in his work ethic. When he's ready for MLB, I think he'll likely be "more ready" than Mes, who I foresee struggling in 2012. Frankly, the chances that either one becomes a .800 OPS bat is actually pretty slim, they just don't occur at the catcher position very often. Because of his versatility and polish, I like the higher floor from Grandal. To me, it's a safer pick.
Mez 2010 in A+, AA, AAA: 11 errors, 13 passed balls, Hillcats staff 74 WP, Mudcats 68 WP
Grandal 2011 in A+, AA, AAA: 13 errors, 19 PB (14 in BAK), Bakersfield staff 128 WP