In three seasons in AAA, he's hit .265/.326/.465 in 656 aB over 179 games. There's some power there - 43 doubles, 28 homers and a .200 isolated slugging percentage. However, he's also ran a K/BB a little over three 353/116.
Not surprisingly, Martinez was not on this year's Baseball America 2011 Top 20 International League Prospects. James Bailey, the author explained why in his chat:
He wasn't really a factor this time around. He's starting to remind me of Alex Escobar, though we need to keep in mind that F-Mart only turns 23 on Monday (Happy Birthday, Fernando!). But he's never had 400 at-bats in a season, and only topped 300 twice. It's hard to develop your skills when you're in the infirmary. Some guys are just too fragile to make it and he may be one of them.