I agree that athleticism is more than speed and defensive ability, but can't say that DiPoto meant it as such when talking about improving the outfield. 1b and C are the only other spots that change seemed necessary and athletic is not a word that describes most of the best at either position.
Either way, Aoki is an improvement over last year at the position and is a great fit for priority#1:C the Z. Smith was already here but only through this year. Guti remains a good fit for a roster spot. But Aoki and Martin (Guti,if you get technical) are not the only outfielders he's acquired. Fast-Forward to 2017 and we could be watching the athletic outfield rotation of Aoki,Martin,Powell and Heredia. Aoki moves from maybe 2nd best defender to probably 4th best if things roll that way. It also added to the depth this year as one of Boog or Gil are likely to get some time this year. We could easily see 700+ quality innings in MLB parks between them this year. Hopefully that would be because they earned it and not because of the combination of misfortune and lack of an actually ready OF option. I could be wrong in thinking that Powell is very likely to be up for good sometime this year. Martin could help his fellow countryman, Heredia, acclimate to the cultures of US and MLB. I'm more excited to see him than anyone else in spring broadcasts, because there's your big wildcard. He could just hit the ground running, all the way to the playoffs. I'm not counting on it.
What happens if both appear ready to contribute with leather and wood through the spring? I'm not seeing people anywhere suggesting any chance for either to break with the club, but I have to think it exists.
The hitting of Powell and maybe more so Heredia may not be what we'd like in a corner immediately or ever. For that reason (and the chance that Heredia is still developing) it seems more likely that not all 3 of Martin, Powell and Heredia would be with the team next year. But athleticism has definitely been acquired for the OF, even if some of it isn't ready to be utilized. Whether they can produce offensively is the main question for all 3 of them, but the athleticism is there regardless of how you define it.