If Uggla is around, there is no doubt that he will get the first crack at the gig. However, there is also no doubt that he will have an extremely short leash. If he struggles in spring training and at the start of the year, the Braves will look for other players to man second base on a regular basis just as they did at the end of last year.
Tommy La Stella is the first name that comes to mind for a number of reasons. First off he will play next season at 24-years-old, so if he is ever going to get a shot now seems to be a pretty good time to do it. On top of him being age appropriate, he netted a 163 wRC+ at double-a last year in 81 games. He doesn't have a ton of power nor a ton of speed, but he has a solid hit tool along with great command of the strike zone.
The projection systems on FanGraphs are favorable toward La Stella. Steamer projects a 113 wRC+, Oliver projects a 117 wRC+, and ZiPS projects a 104 OPS+ (they use OPS+ and not wrc= for ZiPS). The line ZiPS projects is a solid .275/.340/.411, certainly a respectable number from a middle infielder in his first season. Add to the fact that La Stella is a left-handed hitter, and he looks like a guy that could at worst be used in a platoon at second base should Uggla's woes continue or if he were to be shipped out.
The other options are doing a sort of mixed bag approach, utilizing Ramiro Pena and Tyler Pastornicky along with Uggla and or La Stella. It would be odd to carry all four on the roster at the same time, but if the bench were Laird, Schafer, La Stella, Pastornicky, Pena it would have a bit of flexibility with either La Stella or Uggla being the first bat off the bench. That bench would not pack much power. Even if one of the three were in the minors, using three guys interchangeably is not a terrible idea to try and maximize production out of the group.
Pena's projections do not look nearly as favorably as his production last year. Projection systems are far from end all be all, but it does give you some understanding that we probably should not be banking on 107 plate appearances completely changing our view of what Ramiro Pena actually is.
With Pastornicky, ZiPS states his most comparable player is Martin Prado, which can only be music to many Braves fans' ears. Pastornicky has the opportunity to be a very useful bench option for the Braves this year if they do not go out and acquire a new player. The unfortunate part about him is that he is not that great defensively at any position, but he is probably best suited right there at second base. I like his offense a bit more than Pena's, unless Pena really is a 115 wRC+ hitter, but his defense is less quality.
In terms of the three non-Uggla options, Pena has the best defense, La Stella has the best offense, and Pastornicky probably finishes second at both. That creates an issue in deciding who will provide the most value. La Stella is the most likely to succeed long term at the position, while Pena probably has the best chance to help right away.
So, what should we take out of this? To me, we should understand that the Braves have a lot of options and they showed last year that they are not 100% committed to running Uggla out there every day regardless of result. The team has four options at the position and if Uggla is a Brave next year expect the hot hand approach to be ridden all year long. My hope is that La Stella takes a hold of the position, and proves to be adequate enough defensively that he can be an every day player and produce at the bottom of the lineup. My fear is that Uggla is traded and they go with the mixed bag approach and none of it works out. My expectation is that something in the middle occurs, with the Braves getting decent production from the position so that the whole does not produce negative value.