UPDATE: Ana-Lia points out that, if this is the line-up, that only two of Shawn, Nastia and Chellsie would qualify to the All-around Final. That Chellsie might score higher than Nastia due to her better positions in the line-up.
As projected by Andrew Thornton on Gymnast.com:
… Bridget Sloan could end up only doing one routine in the Olympics – bars in prelims!
read the rationale on Gymnast.com
It’s for this reason that the selection of the 6th and final competitor hardly mattered. Whoever was picked would not likely compete.
On the other hand, Sloan was a good choice as she can be back-up on any appartus … in case one of the named gymnasts needs be replaced between prelims and Finals.
Since the U.S.A. will certainly qualify in the top 8 to Team finals, the goal of the preliminary competition will be to qualify athletes to AA and individual apparatus Finals. Team rank is unimportant.
Gymnastics Coaching.com 