Since Cerda got drafted (milb rule 5) in the AAA portion of the rule 5, does that mean he will have to open the season in Memphis? I see he played some 2B, but was primarily at 3B.

Jermaine Curtis was the primary Springfield 3B and got called up to AAA late in the year. Cerda doesn't seem much better than Curtis though.  Am I missing something here?

Any insight into how this is going to shake out?

I can see Wong pencilled in at 2B at AAA as well as Starlin Rodriguez and Lemmerman as the 2B/SS combo in Springfield.

The UTIL infielder position on the MLB team will likely go to Kozma, pushing Ryan Jackson back to AAA, but Greg Garcia likely deserves a promotion to AAA too.

I would think Jackson gets moved off SS to 3B since we need to find out if Garcia can handle SS and if Jackson can handle 3B as the utility guy of the future.  Of course, that blocks Cerda and Curtis as well.

Teams have no restrictions whatsoever on how they use minor league Rule 5 additions. Cerda could be in the Memphis mix, but has just a partial season at Double-A, so it would not be unreasonable to start him at Springfield. My guess is Curtis starting at 3B for Memphis, but then again, he isn't the one they are probably worried about blocking. As you note, they could move Jackson or Garcia there to get them playing time. If the Cards add another middle infielder, pushing Kozma down, that latter scenario seems even more likely.