I'll throw my opinions on these guys out there.
Chis - he can hit, but he struggles against left handed pitching. I think as he gets sustained playing time you'll see that he has a nice bat. The good news about Chis is he's only 22 right now. He's got tremendous upside. So to answer your question, they'll develop Chisenhall.
First base - currently the biggest question mark on the team, IMO. Matt LaPorta will get another look soon, and if I were a betting man, I would guess that someone in the organization will let him know that it's now or never. If he can't produce at the plate through the end of this year, he might be mired in AAA for the rest of his career. A huge disappointment, IMO. Carlos Santana will be an awesome hitter in this league, but his highest value for the team will be at catcher, not at 1B or DH. In other words, his numbers look great coming from the catching position, but not so much from the 1B or DH position. Besides, DH is taken by Hafner for another season. So my guess is that they play Santana more at catcher after LaPorta is back.
OF - I'm also a fan of Sizemore, when healthy. I think there is no way they don't pick up his option for the final year of his contract next year. Just my opinion - I'm sure others would disagree with this. But with Sizemore, Choo, and Brantley all under club control for next season, the only real question is the fourth outfielder. I think the fourth OF will be a huge part of the team next season, given all the injuries we have seen from these three players. For that reason, I'd like to try and re-sign Fukudome if possible. A veteran player who shows discipline at the plate and can play all three OF positions - AND who can bat almost anywhere in the lineup.
And to b00bie's point, I think the blue chip prospects that we have remaining are either too young or coming off an injury year, and therefore would not be considered as valuable a trading chip as we had in both Pomeranz and White - for next season. The club decided to go with Jimenez as a unique trade opportunity, and we'll see next season if that big gamble paid off. Give Antonetti credit for having cajones if nothing else.